Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery

The relative outcomes of sternotomy versus thoracotomy for tricuspid valve operation were examined over a 22-year period.

Three hundred four consecutive patients undergoing tricuspid valve operation using right minithoracotomy (THORC group; n = 124) versus median sternotomy (STERN group; n = 180) between 1985 and 2007 were retrospectively analyzed. Minithoracotomy used a 6-cm incision with femoral venous cannulation and augmented venous return. Sternotomy patients undergoing aortic valve, coronary bypass, or other procedure not feasible through a right minithoracotomy were excluded.

Both groups were similar except that STERN patients had an earlier operative year. Combined mitral and tricuspid valve operation was performed in 70% (214/304) of patients. The tricuspid valve was repaired in 59% (180/304) of patients. Previous sternotomy was present in 56% (171/304) of patients. The mean cardiopulmonary bypass times were longer in the THORC group (216 vs. 167 minutes, <P < 0.0001). THORC was associated with a lower 30-day mortality (2% vs. 11%, P = 0.007), less atrial fibrillation (18% vs. 34%, P = 0.0025), less renal failure (3% vs. 11%, P = 0.016), and shorter length of stay (11 vs. 15 days, P = 0.012), although these differences were less apparent in more recent years. Stroke (3% vs. 2%, P = 0.72), respiratory failure (7% vs. 31%, P = 0.06), and infection rates (11% vs. 16%, P = 0.25) were similar. Five-year survival was also similar (63% vs. 64%, P = 0.84).

Given the limitations of a large, retrospective experience, minithoracotomy versus sternotomy is associated with low short-term morbidity and mortality, with advantages of avoiding sternotomy and minimizing mediastinal dissection in an otherwise high-risk group of patients.

The relative outcomes of sternotomy versus thoracotomy for tricuspid valve operation were examined over a 22-year period.

Three hundred four consecutive patients undergoing tricuspid valve operation using right minithoracotomy (THORC group; n = 124) versus median sternotomy (STERN group; n = 180) between 1985 and 2007 were retrospectively analyzed. Minithoracotomy used a 6-cm incision with femoral venous cannulation and augmented venous return. Sternotomy patients undergoing aortic valve, coronary bypass, or other procedure not feasible through a right minithoracotomy were excluded.

Both groups were similar except that STERN patients had an earlier operative year. Combined mitral and tricuspid valve operation was performed in 70% (214/304) of patients. The tricuspid valve was repaired in 59% (180/304) of patients. Previous sternotomy was present in 56% (171/304) of patients. The mean cardiopulmonary bypass times were longer in the THORC group (216 vs. 167 minutes, <P < 0.0001). THORC was associated with a lower 30-day mortality (2% vs. 11%, P = 0.007), less atrial fibrillation (18% vs. 34%, P = 0.0025), less renal failure (3% vs. 11%, P = 0.016), and shorter length of stay (11 vs. 15 days, P = 0.012), although these differences were less apparent in more recent years. Stroke (3% vs. 2%, P = 0.72), respiratory failure (7% vs. 31%, P = 0.06), and infection rates (11% vs. 16%, P = 0.25) were similar. Five-year survival was also similar (63% vs. 64%, P = 0.84).

Given the limitations of a large, retrospective experience, minithoracotomy versus sternotomy is associated with low short-term morbidity and mortality, with advantages of avoiding sternotomy and minimizing mediastinal dissection in an otherwise high-risk group of patients.

It is not known whether use of a clampless facilitating device during proximal graft anastamosis decreases intraoperative cerebral emboli in patients with mild atherosclerotic ascending aorta (AAA) having off-pump coronary artery bypass.

After intraoperative epiaortic ultrasound showed no more than mild (grade I–II) atherosclerotic ascending aorta, 20 patients were randomized to receive either partial clamping (PC, n = 10) or the HEARTSTRING clampless device (HS, n = 9) for proximal graft construction on the ascending aorta. Continuous transcranial Doppler monitoring, with capability to discern gaseous from solid particulates, was used intraoperatively to monitor high-intensity transient signals (HITS) in the middle cerebral arteries. Postoperative diffusion-weighted brain magnetic resonance imaging documented old and new ischemic brain lesions.

There were no significant differences between the groups in the number of proximals (P = 0.14), distals (P = 0.4), or intraoperative cell saver transfusions (P = 0.69). The total number of HITS was not significantly different between the PC and HS groups (P = 0.2). However, the number of solid HITS was significantly lower in the HS than in the PC group (2.7 ± 2.6 versus 14.0 ± 8.1; P < 0.001). The number of gaseous emboli in the HS group was fourfold greater when a mister-blower rather than a suction device was used to clear blood away from the HS site. Postoperatively, there were no deaths, myocardial infarctions, or clinical strokes observed in either group. Diffusion-weighted cerebral magnetic resonance imaging revealed no statistical difference between groups for new infarct lesions.

Use of the HS device during off-pump coronary artery bypass was associated with significantly fewer intraoperative solid emboli in the middle cerebral artery than PC of the ascending aorta.

It is not known whether use of a clampless facilitating device during proximal graft anastamosis decreases intraoperative cerebral emboli in patients with mild atherosclerotic ascending aorta (AAA) having off-pump coronary artery bypass.

After intraoperative epiaortic ultrasound showed no more than mild (grade I–II) atherosclerotic ascending aorta, 20 patients were randomized to receive either partial clamping (PC, n = 10) or the HEARTSTRING clampless device (HS, n = 9) for proximal graft construction on the ascending aorta. Continuous transcranial Doppler monitoring, with capability to discern gaseous from solid particulates, was used intraoperatively to monitor high-intensity transient signals (HITS) in the middle cerebral arteries. Postoperative diffusion-weighted brain magnetic resonance imaging documented old and new ischemic brain lesions.

There were no significant differences between the groups in the number of proximals (P = 0.14), distals (P = 0.4), or intraoperative cell saver transfusions (P = 0.69). The total number of HITS was not significantly different between the PC and HS groups (P = 0.2). However, the number of solid HITS was significantly lower in the HS than in the PC group (2.7 ± 2.6 versus 14.0 ± 8.1; P < 0.001). The number of gaseous emboli in the HS group was fourfold greater when a mister-blower rather than a suction device was used to clear blood away from the HS site. Postoperatively, there were no deaths, myocardial infarctions, or clinical strokes observed in either group. Diffusion-weighted cerebral magnetic resonance imaging revealed no statistical difference between groups for new infarct lesions.

Use of the HS device during off-pump coronary artery bypass was associated with significantly fewer intraoperative solid emboli in the middle cerebral artery than PC of the ascending aorta.

For elderly patients with symptomatic aortic valve stenosis, aortic valve replacement with tissue valves is still the treatment of choice. Stentless valves were introduced to clinical practice for better hemodynamic features as compared with stented tissue valves. However, the implantation is more complex and time demanding, especially in minimal invasive aortic valve replacement. We present our clinical data on 22 patients having received a sutureless ATS 3f Enable aortic bioprosthesis via partial upper sternotomy.

The procedure was performed using CPB with cardioplegic arrest. After resection of the stenotic aortic valve and debridement of the annulus, the valve was inserted and released. Mean age was 79 years, and mean logistic Euroscore was 13. Subvalvular myectomy was performed in two patients. Prosthetic valve sizes were 19 mm (n = 1), 21 mm (n = 7), 23 mm (n = 6), 25 mm (n = 6), and 27 mm (n = 2).

Implantation of the valve required 10 ± 6 minutes. Cardiopulmonary bypass and aortic crossclamp time were 87 ± 16 and 55 ± 11 minutes, respectively. Early mortality (<90 days) was 9% (2 patients). No paravalvular leakage was detected intraoperatively or in follow-up echocardiography. The mean transvalvular gradients were 9 ± 6 mm Hg at discharge and 8 ± 2 mm Hg at 1-year follow-up.

Sutureless valve implantation via partial sternotomy is feasible and safe with the ATS 3f Enable bioprosthesis. Reduction of cardiopulmonary bypass and aortic crossclamp time seems possible with increasing experience. Hemodynamic data are very promising with low gradients at discharge and after 12 month. Sutureless valve implantation via minimal invasive access may be an alternative treatment option for elderly patients with high comorbidity.

For elderly patients with symptomatic aortic valve stenosis, aortic valve replacement with tissue valves is still the treatment of choice. Stentless valves were introduced to clinical practice for better hemodynamic features as compared with stented tissue valves. However, the implantation is more complex and time demanding, especially in minimal invasive aortic valve replacement. We present our clinical data on 22 patients having received a sutureless ATS 3f Enable aortic bioprosthesis via partial upper sternotomy.

The procedure was performed using CPB with cardioplegic arrest. After resection of the stenotic aortic valve and debridement of the annulus, the valve was inserted and released. Mean age was 79 years, and mean logistic Euroscore was 13. Subvalvular myectomy was performed in two patients. Prosthetic valve sizes were 19 mm (n = 1), 21 mm (n = 7), 23 mm (n = 6), 25 mm (n = 6), and 27 mm (n = 2).

Implantation of the valve required 10 ± 6 minutes. Cardiopulmonary bypass and aortic crossclamp time were 87 ± 16 and 55 ± 11 minutes, respectively. Early mortality (<90 days) was 9% (2 patients). No paravalvular leakage was detected intraoperatively or in follow-up echocardiography. The mean transvalvular gradients were 9 ± 6 mm Hg at discharge and 8 ± 2 mm Hg at 1-year follow-up.

Sutureless valve implantation via partial sternotomy is feasible and safe with the ATS 3f Enable bioprosthesis. Reduction of cardiopulmonary bypass and aortic crossclamp time seems possible with increasing experience. Hemodynamic data are very promising with low gradients at discharge and after 12 month. Sutureless valve implantation via minimal invasive access may be an alternative treatment option for elderly patients with high comorbidity.

Endoventricular circular patch plasty is a method used to reconstruct the ventricular cavity in patients with (post) ischemic left ventricular aneurysm or global dilatation. However, late redilatation with mitral regurgitation has been reported, in which postoperative apex shape seems to play an important role. We studied the feasibility of ventricular volume downsizing with a variably shaped patch in porcine hearts.

In five in vitro and two acute animal experiments, a dyskinetic aneurysm was simulated with a pericardial insert. Reducing patch surface by changing patch shape diminished end-diastolic volume. In vitro, static end-diastolic volume was determined for each patch shape using volumetry and echocardiography. In the acute animal experiments, preliminary observations of patch behavior in live material were made, and pressure/time relationship, dPdTmax, was registered.

In vitro, bringing the convex patch into a flat plane reduced LV volume from 66 ± 7 mL (aneurysm) to 49 ± 5 mL. Four of 5 patch shapes further reduced volume to a mean of 38 ± 7 mL (P = 0.03). The in vitro echocardiographic measurements correlated with volumetry findings (r = 0.81). In the acute animal experiments, dPdTmax varied with patch shape, independent of volume changes.

In this pilot study, in vitro shape configuration of the resizable ventricular patch resulted in a calibrated end-diastolic volume reduction. The data of the two in vivo pilot experiments clearly indicate that change in patch configuration in the situation of more or less unchanged end-diastolic volume had impact on cardiac performance. Future studies must substantiate the results of this observation.

Endoventricular circular patch plasty is a method used to reconstruct the ventricular cavity in patients with (post) ischemic left ventricular aneurysm or global dilatation. However, late redilatation with mitral regurgitation has been reported, in which postoperative apex shape seems to play an important role. We studied the feasibility of ventricular volume downsizing with a variably shaped patch in porcine hearts.

In five in vitro and two acute animal experiments, a dyskinetic aneurysm was simulated with a pericardial insert. Reducing patch surface by changing patch shape diminished end-diastolic volume. In vitro, static end-diastolic volume was determined for each patch shape using volumetry and echocardiography. In the acute animal experiments, preliminary observations of patch behavior in live material were made, and pressure/time relationship, dPdTmax, was registered.

In vitro, bringing the convex patch into a flat plane reduced LV volume from 66 ± 7 mL (aneurysm) to 49 ± 5 mL. Four of 5 patch shapes further reduced volume to a mean of 38 ± 7 mL (P = 0.03). The in vitro echocardiographic measurements correlated with volumetry findings (r = 0.81). In the acute animal experiments, dPdTmax varied with patch shape, independent of volume changes.

In this pilot study, in vitro shape configuration of the resizable ventricular patch resulted in a calibrated end-diastolic volume reduction. The data of the two in vivo pilot experiments clearly indicate that change in patch configuration in the situation of more or less unchanged end-diastolic volume had impact on cardiac performance. Future studies must substantiate the results of this observation.

Conventional reoperative coronary artery bypass grafting is associated with risk of sternal re-entry, injury to patent grafts, and embolization from diseased grafts. Sternal sparing minimally invasive direct coronary artery bypass (MIDCAB) avoids such risks in cases where it is technically feasible. We sought to examine in-hospital outcomes of reoperative MIDCAB surgery.

We recorded prospective standardized data from the New York Cardiac Surgical Reporting System database of 369 reoperative MIDCAB cases from 1996 to 2006 and compared with 822 primary MIDCAB patients in the same time period. We compared the preoperative risk profile and postoperative in-hospital outcomes and length of stay for both groups.

There was a significantly higher risk profile typical of the reoperative patient population (P < 0.001 for stroke, peripheral/cerebrovascular disease, extensive aortic calcification, renal failure, and left ventricular ejection fraction <40%) compared with the primary MIDCAB group. Despite this fact, there was no difference in the in-hospital outcomes and length of hospital stay between the two groups.

Reoperative MIDCAB provides targeted coronary revascularization and avoids hazards of sternal re-entry, graft injury and manipulation, and deleterious effects of cardiopulmonary bypass. This hastens recovery and provides excellent early outcomes equivalent to primary MIDCAB procedures.

Conventional reoperative coronary artery bypass grafting is associated with risk of sternal re-entry, injury to patent grafts, and embolization from diseased grafts. Sternal sparing minimally invasive direct coronary artery bypass (MIDCAB) avoids such risks in cases where it is technically feasible. We sought to examine in-hospital outcomes of reoperative MIDCAB surgery.

We recorded prospective standardized data from the New York Cardiac Surgical Reporting System database of 369 reoperative MIDCAB cases from 1996 to 2006 and compared with 822 primary MIDCAB patients in the same time period. We compared the preoperative risk profile and postoperative in-hospital outcomes and length of stay for both groups.

There was a significantly higher risk profile typical of the reoperative patient population (P < 0.001 for stroke, peripheral/cerebrovascular disease, extensive aortic calcification, renal failure, and left ventricular ejection fraction <40%) compared with the primary MIDCAB group. Despite this fact, there was no difference in the in-hospital outcomes and length of hospital stay between the two groups.

Reoperative MIDCAB provides targeted coronary revascularization and avoids hazards of sternal re-entry, graft injury and manipulation, and deleterious effects of cardiopulmonary bypass. This hastens recovery and provides excellent early outcomes equivalent to primary MIDCAB procedures.

The purpose of this study was to evaluate the implantability of a novel epicardial mitral annuloplasty device and its ability to reduce the septal-lateral (S-L) dimension of the mitral annulus.

The devices were implanted on the beating heart in 2 healthy dogs (the 24-mm long device in dog A and the 27-mm and 24-mm standard devices in dog B) by sliding the anterior arm onto the floor of the transverse sinus and positioning the posterior arm just apical to the atrioventricular groove on the left ventricular posterolateral wall. The devices were secured with titanium helical tacks driven through the device into the ventricular wall. Two-dimensional epicardial echocardiograms were performed before and after device implantation to evaluate the degree of mitral regurgitation (MR) and the S-L dimension.

Device implantation was uneventful, taking only ~30 seconds to deploy. MR (1 +) in both dogs at baseline was reduced to zero after implant. The reductions in S-L dimension in systole for the 24-mm device were 7.5% in dog A and 30.5% in dog B. For the 27-mm device in dog B, S-L reduction in systole was 29.9%. The leaflet coaptation length was increased in both cases.

The new device was effective in reducing S-L dimension and 1 + MR without requiring the use of cardiopulmonary bypass. We are currently evaluating this device for the treatment of MR in a rapid-pacing canine heart failure model.

The purpose of this study was to evaluate the implantability of a novel epicardial mitral annuloplasty device and its ability to reduce the septal-lateral (S-L) dimension of the mitral annulus.

The devices were implanted on the beating heart in 2 healthy dogs (the 24-mm long device in dog A and the 27-mm and 24-mm standard devices in dog B) by sliding the anterior arm onto the floor of the transverse sinus and positioning the posterior arm just apical to the atrioventricular groove on the left ventricular posterolateral wall. The devices were secured with titanium helical tacks driven through the device into the ventricular wall. Two-dimensional epicardial echocardiograms were performed before and after device implantation to evaluate the degree of mitral regurgitation (MR) and the S-L dimension.

Device implantation was uneventful, taking only ~30 seconds to deploy. MR (1 +) in both dogs at baseline was reduced to zero after implant. The reductions in S-L dimension in systole for the 24-mm device were 7.5% in dog A and 30.5% in dog B. For the 27-mm device in dog B, S-L reduction in systole was 29.9%. The leaflet coaptation length was increased in both cases.

The new device was effective in reducing S-L dimension and 1 + MR without requiring the use of cardiopulmonary bypass. We are currently evaluating this device for the treatment of MR in a rapid-pacing canine heart failure model.

Long-term survival after off-pump surgery in patients with low ejection fraction was investigated.

Three hundred forty-six patients with ejection fraction 30% or less with isolated off-pump coronary artery bypass surgery (OPCAB) were compared with a propensity matched historical group operated on-pump (ONCAB) and with data from literature after percutaneous coronary intervention and OPCAB surgery.

The lower invasiveness of OPCAB contributed to a significantly better 30-day survival, shorter postoperative length of stay, and fewer in-hospital complications. Incomplete revascularization of the posterior and lateral territories of the heart correlated with higher 1-year mortality. The probability of survival for 8 years after OPCAB was 50.1% (n = 76) versus 49.7% (n = 82) for ONCAB without comparable data from literature for OPCAB or percutaneous coronary intervention in these high-risk patients.

OPCAB surgery in patients with low ejection fraction is a viable alternative but so far without demonstrable long-term survival advantage to ONCAB.

Long-term survival after off-pump surgery in patients with low ejection fraction was investigated.

Three hundred forty-six patients with ejection fraction 30% or less with isolated off-pump coronary artery bypass surgery (OPCAB) were compared with a propensity matched historical group operated on-pump (ONCAB) and with data from literature after percutaneous coronary intervention and OPCAB surgery.

The lower invasiveness of OPCAB contributed to a significantly better 30-day survival, shorter postoperative length of stay, and fewer in-hospital complications. Incomplete revascularization of the posterior and lateral territories of the heart correlated with higher 1-year mortality. The probability of survival for 8 years after OPCAB was 50.1% (n = 76) versus 49.7% (n = 82) for ONCAB without comparable data from literature for OPCAB or percutaneous coronary intervention in these high-risk patients.

OPCAB surgery in patients with low ejection fraction is a viable alternative but so far without demonstrable long-term survival advantage to ONCAB.

Chest-tube clogging can lead to complications after heart and lung surgery. Surgeons often choose large-diameter chest tubes or place more than one chest tube when concerned about the potential for clogging. The purpose of this report is to describe the design and function of a proprietary active tube clearance system, a novel device that clears clots and debris from chest tubes.

The active tube clearance system is a novel chest tube clearance apparatus developed to maintain chest tube patency. Chest tube clearance is achieved by advancing the specially designed clearance member back and forth within the chest tube under sterile conditions, breaking down and pulling clots back toward the drainage receptacle, thereby leaving the inner portion of the chest tube clear of any obstructing material.

By maintaining chest tube patency, chest tube drainage can be performed more safely, and this apparatus may possibly lead to the use of smaller chest tubes and less invasive insertion techniques.

Chest-tube clogging can lead to complications after heart and lung surgery. Surgeons often choose large-diameter chest tubes or place more than one chest tube when concerned about the potential for clogging. The purpose of this report is to describe the design and function of a proprietary active tube clearance system, a novel device that clears clots and debris from chest tubes.

The active tube clearance system is a novel chest tube clearance apparatus developed to maintain chest tube patency. Chest tube clearance is achieved by advancing the specially designed clearance member back and forth within the chest tube under sterile conditions, breaking down and pulling clots back toward the drainage receptacle, thereby leaving the inner portion of the chest tube clear of any obstructing material.

By maintaining chest tube patency, chest tube drainage can be performed more safely, and this apparatus may possibly lead to the use of smaller chest tubes and less invasive insertion techniques.

The purpose of this study is to report our 2-year experience of performing endoscopic intracardiac procedures using the da Vinci Surgical System. Our teams at Kanazawa University and Tokyo Medical University groups began using the da Vinci Surgical System (Intuitive Surgical, Inc, Sunnyvale, CA) in 2005. This series represents the first Japanese application of robotic technology for totally endoscopic open-heart surgery.

From January 2008 to February 2009, 10 patients (mean age: 46.8 ± 16.3 years, 70% women) underwent endoscopic atrial septal defect closure and resection of the left atrial myxoma using the da Vinci Surgical System and peripheral cardiopulmonary bypass technique. Of the 10 patients, nine were classified as New York Heart Association class II and 1 patient exhibited atrial arrhythmias. In addition, two patients required mitral valve plasty (n = 2) and tricuspid annuloplasty (n = 1).

Mean da Vinci Surgical System working time was 140.7 ± 57.4 minutes. Mean cardiopulmonary bypass and aortic cross clamp times were 103.1 ± 37.1 and 30.0 ± 16.9 minutes, respectively. There were no conversions to sternotomy or small thoracotomy. There were no hospital deaths. Mean intensive care unit and hospital stays were 1 day and 3.1 ± 0.3 days, respectively. All patients appreciated the cosmetic result and fast recovery.

Closed-chest atrial septal defect closure and myxoma resection performed using robotic techniques achieved excellent results and rapid postoperative recovery and provided an attractive cosmetic advantage over median sternotomy.

The purpose of this study is to report our 2-year experience of performing endoscopic intracardiac procedures using the da Vinci Surgical System. Our teams at Kanazawa University and Tokyo Medical University groups began using the da Vinci Surgical System (Intuitive Surgical, Inc, Sunnyvale, CA) in 2005. This series represents the first Japanese application of robotic technology for totally endoscopic open-heart surgery.

From January 2008 to February 2009, 10 patients (mean age: 46.8 ± 16.3 years, 70% women) underwent endoscopic atrial septal defect closure and resection of the left atrial myxoma using the da Vinci Surgical System and peripheral cardiopulmonary bypass technique. Of the 10 patients, nine were classified as New York Heart Association class II and 1 patient exhibited atrial arrhythmias. In addition, two patients required mitral valve plasty (n = 2) and tricuspid annuloplasty (n = 1).

Mean da Vinci Surgical System working time was 140.7 ± 57.4 minutes. Mean cardiopulmonary bypass and aortic cross clamp times were 103.1 ± 37.1 and 30.0 ± 16.9 minutes, respectively. There were no conversions to sternotomy or small thoracotomy. There were no hospital deaths. Mean intensive care unit and hospital stays were 1 day and 3.1 ± 0.3 days, respectively. All patients appreciated the cosmetic result and fast recovery.

Closed-chest atrial septal defect closure and myxoma resection performed using robotic techniques achieved excellent results and rapid postoperative recovery and provided an attractive cosmetic advantage over median sternotomy.

Single-port subxiphoid videopericardioscopy with a rigid shaft is useful for left atrial exclusion, left ventricular (LV) pacing lead implantation, and epicardial mapping, but it may interfere with the cardiac rhythm and adversely alter hemodynamics. We examined the impact of this technique on hemodynamic indices in a porcine model.

The videopericardioscopy device was introduced into the pericardial space of five pigs (35–45 kg) via a subxiphoid approach and navigated to six anatomic targets [right atrial appendage, superior vena cava, ascending aorta, left atrial appendage (anterior and posterior approaches), transverse sinus, and atrioventricular (AV) groove]. After successful target acquisition, the device was withdrawn through the subxiphoid port. When the hemodynamics stabilized, the device was navigated to another target. The heart rate (HR), arterial blood pressure (BP), central venous pressure (CVP), pulmonary arterial pressure, and mixed venous oxygen saturation (SvO₂) were measured at every pretarget (subxiphoid incision) and target point. After the navigation trials, the animals were killed and the mediastinum space was examined for procedure-related injuries.

The device afforded a good view, and the navigation trials were successfully performed on the beating heart. Four animals tolerated the procedures, whereas one died of device-induced ventricular fibrillation after the trials. Hemodynamics was severely compromised at all anatomic targets except the left atrial appendage (anterior approach).

Subxiphoid videopericardioscopy significantly interferes with the cardiac rhythm, causing life-threatening arrhythmia and hemodynamic compromise, when the target is located deep and far from the pericardiotomy. A flexible or highly articulated device would enable intrapericardial navigation without hemodynamic compromise.

Single-port subxiphoid videopericardioscopy with a rigid shaft is useful for left atrial exclusion, left ventricular (LV) pacing lead implantation, and epicardial mapping, but it may interfere with the cardiac rhythm and adversely alter hemodynamics. We examined the impact of this technique on hemodynamic indices in a porcine model.

The videopericardioscopy device was introduced into the pericardial space of five pigs (35–45 kg) via a subxiphoid approach and navigated to six anatomic targets [right atrial appendage, superior vena cava, ascending aorta, left atrial appendage (anterior and posterior approaches), transverse sinus, and atrioventricular (AV) groove]. After successful target acquisition, the device was withdrawn through the subxiphoid port. When the hemodynamics stabilized, the device was navigated to another target. The heart rate (HR), arterial blood pressure (BP), central venous pressure (CVP), pulmonary arterial pressure, and mixed venous oxygen saturation (SvO₂) were measured at every pretarget (subxiphoid incision) and target point. After the navigation trials, the animals were killed and the mediastinum space was examined for procedure-related injuries.

The device afforded a good view, and the navigation trials were successfully performed on the beating heart. Four animals tolerated the procedures, whereas one died of device-induced ventricular fibrillation after the trials. Hemodynamics was severely compromised at all anatomic targets except the left atrial appendage (anterior approach).

Subxiphoid videopericardioscopy significantly interferes with the cardiac rhythm, causing life-threatening arrhythmia and hemodynamic compromise, when the target is located deep and far from the pericardiotomy. A flexible or highly articulated device would enable intrapericardial navigation without hemodynamic compromise.

The feasibility of endovascular resection of highly calcified aortic valves has already been demonstrated by our group. Different endovascular and intracardiac tractability methods were applied. In this study, these technologies were analyzed comparing the tractability, the resection time, and the lesions in the surrounding tissue.

All aortic valve resections (seven human hearts and 21 porcine hearts) were performed using a Thulium:YAG laser (continuous wave, wavelength of 2.01 μm, 20 watts power rating). In the first resection system, the laser fiber was controlled by a free in-lying flexible endoscope (Ø 2.5 mm, length of 600 mm). The distal part of the endoscope (40 mm) was moved in one plane by proximal manual control (three degrees of freedom). The resection system was separated into defined rooms assigning one room for one tool. The fiber was controlled by the above-mentioned endoscope (^*) (three degrees of freedom). The third resection system was a mechanical microactuator carrying the laser fiber (three degrees of freedom). The fourth resection system contains a rotatable inlay with defined rooms and a newly designed nitinol (NiTi) microactuator that controlled the laser fiber (four degrees of freedom). The resection time per leaflet was measured in minutes. Gross anatomy and histology in the surrounding tissue were evaluated.

The resection time in approaches 1, 2, 3, and 4 was 5.5 ± 2.3 minutes, 7.4 ± 2.7 minutes, ± 6.6 minutes, and2.3 ± 1.2 minutes, respectively. The gross anatomy and histology of collateral damages revealed only superficial lesions of the surrounding tissue. The amount of lesions and the resection time were lower in the fourth approach with four degrees of freedom.

This analysis demonstrated that a precise tractability with four degrees of freedom is necessary for a faster and safer endovascular resection of the aortic valve. The analysis will help to optimize the ongoing development of the endovascular and intra-cardiac resection technology.

The feasibility of endovascular resection of highly calcified aortic valves has already been demonstrated by our group. Different endovascular and intracardiac tractability methods were applied. In this study, these technologies were analyzed comparing the tractability, the resection time, and the lesions in the surrounding tissue.

All aortic valve resections (seven human hearts and 21 porcine hearts) were performed using a Thulium:YAG laser (continuous wave, wavelength of 2.01 μm, 20 watts power rating). In the first resection system, the laser fiber was controlled by a free in-lying flexible endoscope (Ø 2.5 mm, length of 600 mm). The distal part of the endoscope (40 mm) was moved in one plane by proximal manual control (three degrees of freedom). The resection system was separated into defined rooms assigning one room for one tool. The fiber was controlled by the above-mentioned endoscope (^*) (three degrees of freedom). The third resection system was a mechanical microactuator carrying the laser fiber (three degrees of freedom). The fourth resection system contains a rotatable inlay with defined rooms and a newly designed nitinol (NiTi) microactuator that controlled the laser fiber (four degrees of freedom). The resection time per leaflet was measured in minutes. Gross anatomy and histology in the surrounding tissue were evaluated.

The resection time in approaches 1, 2, 3, and 4 was 5.5 ± 2.3 minutes, 7.4 ± 2.7 minutes, ± 6.6 minutes, and2.3 ± 1.2 minutes, respectively. The gross anatomy and histology of collateral damages revealed only superficial lesions of the surrounding tissue. The amount of lesions and the resection time were lower in the fourth approach with four degrees of freedom.

This analysis demonstrated that a precise tractability with four degrees of freedom is necessary for a faster and safer endovascular resection of the aortic valve. The analysis will help to optimize the ongoing development of the endovascular and intra-cardiac resection technology.