The Impact of Perioperative Aspirin on Bleeding Complications Following Robotic Partial Nephrectomy

Abstract

Introduction:

Perioperative administration of aspirin for high-risk urologic procedures is controversial. We evaluated whether continuation of perioperative aspirin alters bleeding complications in patients who undergo robotic partial nephrectomy (RPN).

Materials and Methods:

Retrospective review identified 214 consecutive patients who underwent RPN at our institution from May 2012 to March 2015. Comparisons were performed between 49 patients continuing aspirin (81 mg), 34 patients holding aspirin for at least 7 days before surgery, and 131 patients who had never taken aspirin. Overall bleeding complications included postoperative hemoglobin drop of >3 g/dL during admission, postoperative blood transfusion, or necessity for urgent selective angiographic embolization. Multivariable logistic regression was performed to assess the independent association between aspirin administration and bleeding complications.

Results:

Patients continuing aspirin were older and had higher Charlson Comorbidity Index (CCI) compared with patients who held or never took aspirin (both p < 0.01). Compared with those who held or never took aspirin, patients continuing aspirin had similar rates of overall bleeding complications (27% vs 15% vs 14%, p = 0.13), hemoglobin drop >3 g/dL (24% vs 15% vs 14%, p = 0.24), and postoperative blood transfusion (4% vs 3% vs 2%, p = 0.43). There was a trend for more frequent need for embolization in patients continuing aspirin (6% vs 3% vs 1%, p = 0.07). On multivariate analysis controlling for CCI and RENAL nephrometry score, aspirin administration was not significantly associated with bleeding complications. Continuation of aspirin was associated with higher overall 30-day complications compared with the other groups (24% vs 12% vs 8%, p = 0.03).

Conclusions:

Continuation of perioperative 81 mg aspirin for patients undergoing RPN was not associated with significantly higher overall bleeding complications. Patients continuing aspirin had increased comorbidities and overall 30-day complications. While our data suggest that continuing perioperative aspirin is safe in select patients, larger studies are needed to confirm these findings.

Introduction

There is controversy regarding perioperative administration of aspirin due to increased risk of bleeding.^1,2 Level 1 evidence has demonstrated decreased risk of stroke and myocardial events when continuing perioperative aspirin for noncardiac surgery.^3,4 Conversely, holding aspirin has been associated with elevated risk of thromboembolic complications.^5
–7 Therefore, multiple surgical guidelines promote continuing perioperative aspirin administration for patients with high cardiovascular risk.^8,9 Recent consensus guidelines by the American Urologic Association similarly recommend continuing aspirin for these patients.¹⁰

Among urologic surgeries, partial nephrectomy has one of the highest risks of major postoperative hemorrhage.¹¹ Patients with higher overall comorbidity are increasingly managed with nephron-sparing surgery, especially following the widespread adoption of minimally invasive and robotic techniques.¹² Many of these patients take aspirin, raising challenges when balancing the risk of thromboembolic complications vs the risk of significant bleeding. Several recent retrospective analyses assessing the risks and benefits of continuing aspirin for partial nephrectomy have demonstrated an acceptable rate of bleeding complications.^13
–15 However, these studies are limited by sample size, with 17 patients continuing aspirin in the largest series.¹⁴ Our institution's perioperative protocol promotes continuation of low-dose aspirin for high-risk patients, leading to a large cohort of patients who continued perioperative aspirin for robotic partial nephrectomy (RPN). We hypothesize that continuing perioperative administration of aspirin for patients undergoing RPN does not increase bleeding or other complications compared with patients holding or never taking aspirin.

Materials and Methods

Database description and patient selection

We performed a review of our prospectively maintained Institutional Review Board-approved database to identify 214 consecutive patients who underwent transperitoneal RPN without need for conversion to open approach or radical nephrectomy between May 2012 and March 2015. All surgeries were performed by two fellowship-trained urologists who specialize in robotic procedures (S.E., A.S.). Each surgeon had significant experience with minimally invasive partial nephrectomies, having previously performed over 300 (S.E.) and 700 (A.S.) of these procedures. Cases were performed robotically using previously described minimally invasive techniques.¹⁶ Renal artery or combined hilar vessel clamping was performed based on anatomy. The tumor was excised, followed by hemostasis utilizing a combination of cautery, Argon beam, and suture ligation. Hemostatic agents, including Floseal^® and Surgicel Nu-knit^®, were routinely placed in the resection bed. Bolsters were not used. Renorrhaphy was performed using 2-0 V-lock sutures to close the collecting system and 0 V-lock sutures to close the renal parenchymal defect. Hemostasis was verified after hilar unclamping and reducing pneumoperitoneum to 4 mm Hg for 5 minutes.

Perioperative anticoagulation

The decision to discontinue perioperative aspirin was determined by joint discussions, including the surgeon, primary physician, hematology consultation, or preoperative anesthesia consultation. Patients were stratified into three groups for analysis: patients previously receiving aspirin who continued taking aspirin during the perioperative period, patients previously receiving aspirin who held aspirin for their surgery, and patients who never received aspirin. In the continuation group, all patients continued aspirin 81 mg during the entire perioperative period, including the morning of surgery. Aspirin 325 mg was bridged to aspirin 81 mg for 7 to 10 days before surgery. If held, aspirin or additional antiplatelet therapy was discontinued 7 to 10 days before surgery. Chronic warfarin was discontinued 3 to 5 days before surgery and bridged with enoxaparin if appropriate. Rivaroxaban was discontinued 1 day before surgery. All anticoagulation was typically restarted at time of discharge if patients were hemodynamically stable or on first follow-up appointment, depending on indication of therapy. All patients received routine prophylactic subcutaneous heparin during postoperative hospitalization.

Outcomes

Baseline characteristics, including age, gender, race, body mass index, and American Society of Anesthesiologists (ASA) physical status score, were collected. Charlson Comorbidity Index (CCI) was calculated. History of arterial vascular disease or other vascular comorbidities was evaluated. Pathologic variables included dominant tumor size, laterality, RENAL nephrometry score,¹⁷ pathologic stage, and categorization of benign vs malignant. Operative variables included estimated blood loss (EBL), operating room time from incision to closure, volume of crystalloid intravenous fluids, and rates of intraoperative transfusion and complications. The primary postoperative outcome was a composite endpoint of overall bleeding complications, including hemoglobin drop >3 g/dL, need for postoperative transfusion, and need for interventional radiology (IR) selective angiographic embolization. Hemoglobin drop was calculated from the difference between preoperative and nadir inpatient hemoglobin levels, and a cutoff of 3 g/dL was designated based on an average hemoglobin drop of 2.1 to 2.7 g/dL in a previous large analysis.¹⁸ No specific protocol was utilized for postoperative transfusion, defined as any transfusion occurring within 30 days. IR embolization was performed either during initial postoperative admission or on readmission if there was high clinical suspicion for arterial bleeding based on hemodynamic instability or persistent decreasing hemoglobin despite transfusion. Thirty-day Clavien complications were categorized based on severity (low grade [1–2] or high grade [3–5]).¹⁹

Statistical analysis

Statistical analysis was performed using Stata^®, version 13.0 (College Station, TX). Continuous variables were presented as median and interquartile range and were compared using the Kruskal–Wallis test. Categorical variables were presented as whole numbers and percentages and were compared using Fisher's exact test. Multivariable logistic regression was performed to adjust for CCI and RENAL nephrometry score and assess the association between the primary composite outcome and aspirin administration status. Two-sided p-values were reported, and a p-value <0.05 was considered statistically significant.

Results

Among 214 patients, 49 (23%) continued aspirin (81 mg), 34 (16%) held aspirin for at least 7 days before surgery, and 131 (61%) had never taken aspirin (Table 1). Of the 83 patients initially taking aspirin, 11 (13%) took aspirin 325 mg and 76 (87%) took aspirin 81 mg. Patients who continued aspirin had significantly higher comorbidity compared with patients who held or never took aspirin, as assessed by ASA score of 3 or 4 and CCI. Vascular comorbidities, including coronary artery disease, peripheral vascular disease, and myocardial infarction (MI), were significantly more common in patients who continued aspirin (all p < 0.03), except for stroke, transient ischemic attack, deep vein thrombosis (DVT), and pulmonary embolism (PE).

Table 1.

Baseline Sociodemographic and Clinical Characteristics of Patients by Perioperative Aspirin (American Society of Anesthesiologists) Administration Status

	Continued ASA (n = 49) ^a	Held ASA (n = 34)	No prior ASA (n = 131)	p-Value
Age, years (median, [IQR])	68 [58, 74]	68 [58, 73]	55 [48, 63]	<0.01
Gender, male [n (%)]	30 (61)	21 (62)	68 (53)	0.46
Race, n (%)				0.23
Caucasian	37 (76)	23 (71)	107 (82)
Black	11 (22)	8 (23)	16 (12)
Other	1 (2)	2 (6)	8 (6)
BMI, kg/m² (median, [IQR])	29 [26, 34]	29 [26, 33]	29 [26, 33]	0.83
ASA score, n (%)				<0.01
1	1 (2)	1 (3)	4 (3)
2	7 (14)	7 (21)	59 (45)
3	37 (76)	26 (76)	68 (52)
4	4 (8)	0 (0)	0 (0)
CCI, median [IQR]	5 [4, 6]	4 [3, 5]	2 [1, 3]	<0.01
History of arterial vascular disease, n (%)
Coronary artery disease	21 (43)	1 (2.9)	2 (1.5)	<0.01
Peripheral vascular disease	9 (18)	2 (5.9)	2 (1.5)	<0.01
Stroke/TIA	2 (4.1)	2 (5.9)	1 (0.8)	0.09
Myocardial infarction	22 (45)	2 (5.9)	1 (0.8)	<0.01
Other vascular comorbidities, n (%)
Hypertension	41 (84)	29 (85)	62 (47)	<0.01
Diabetes mellitus	18 (37)	10 (29)	22 (17)	0.01
Congestive heart failure	5 (10)	0	3 (2.3)	0.03
Deep vein thrombosis	2 (4.1)	1 (2.9)	2 (1.5)	0.44
Pulmonary embolism	1 (2.0)	0	2 (1.5)	1
Addition anticoagulation
Warfarin held	3 (6.1)	0	2 (1.5)	0.13
Warfarin bridged	1 (2.0)	0	1 (0.8)	0.63
Rivaroxaban	1 (2.0)	0	0	0.39
Preoperative hemoglobin, median [IQR]	13.9 [12.2, 15]	13.6 [12.5, 14.2]	14 [12.7, 14.6]	0.71

All patients who continued ASA received 81 mg regardless of prior dose.

Bold indicates statistically significant values.

ASA = American Society of Anesthesiologists; BMI = body mass index; CCI = Charlson Comorbidity Index; IQR = interquartile range; SD = standard deviation; TIA = transient ischemic attack.

Median tumor size, RENAL nephrometry score, laterality, and pathologic stage of renal-cell carcinoma were between groups (all p > 0.05; Table 2). Median tumor size for the 10 patients with angiomyolipoma was 4.5 [1.6–6.2] cm, and all these patients never took aspirin.

Table 2.

Tumor and Pathologic Characteristics of Patients by Perioperative Aspirin (American Society of Anesthesiologists) Administration Status

	Continued ASA (n = 49)	Held ASA (n = 34)	No prior ASA (n = 131)	p-Value
Tumor size, cm (median [IQR])	3.2 [2.4, 4.5]	3.0 [2.5, 4.0]	3.0 [2.0, 4.2]	0.69
Laterality, n (%)				0.76
Right	28 (57)	17 (50)	67 (51)
Left	21 (43)	17 (50)	64 (49)
RENAL nephrometry grading
Score, median [IQR]	7.5 [5–9]	8 [6–9]	7 [5–8]	0.27
Moderate score [7–9], n (%)	15 (34)	15 (54)	47 (39)	0.25
High score [10–12], n (%)	10 (23)	4 (14)	15 (13)	0.28
Endophytic, n (%)	7 (16)	5 (18)	12 (10)	0.62
Posterior, n (%)	18 (40)	11 (39)	39 (33)	0.24
RCC pathologic stage, n (%)				0.06
pT1a	25 (57)	22 (74)	87 (77)
pT1b	14 (43)	7 (23)	24 (21)
pT2a	0 (0)	1 (3)	1 (1)
pT2b	0 (0)	0 (0)	1 (1)
Non-RCC lesions, n (%^a)				<0.02
AML	0 (0)	0 (0)	10 (8)^b
Other	5 (10)	4 (12)	8 (6)

% of all renal masses.

Median (IQR) AML size 4.5 [1.6, 6.2] cm.

Bold indicates statistically significant values.

AML = angiomyolipoma; RCC = renal-cell carcinoma.

There were no significant differences in EBL, operating room time, or intravenous fluids between groups (all p < 0.18; Table 3). Three (9%) patients who held aspirin required intraoperative transfusion compared with 1 (2%) and 0 patients who continued and never took aspirin, respectively (p < 0.01). Two patients who continued aspirin had injuries to the pancreas or liver, while two patients who never took aspirin had injuries to the bowel or gallbladder. All injuries were managed in a robotic or laparoscopic manner with general surgery consultation.

Table 3.

Operative Factors of Patients by Perioperative Aspirin (American Society of Anesthesiologists) Administration Status

	Continued ASA (n = 49)	Held ASA (n = 34)	No prior ASA (n = 131)	p-Value
Surgeon, n (%)^a				0.03
S.E.	20 (25)	6 (7)	55 (68)
A.S.	29 (22)	28 (21)	76 (57)
Hilar clamping, n (%)				0.48
Combined	47 (96)	33 (97)	124 (94.6)
Artery alone	2 (4)	0	6 (4.6)
Off-clamp	0	1 (3)	1 (0.8)
EBL, mL (median [IQR])	100 [70, 150]	125 [50, 250]	100 [50, 160]	0.18
Operating room time, min (median [IQR])	187 [170, 217]	195 [171, 240]	183 [159, 221]	0.43
IVF, L crystalloid, median [IQR]	2.3 [2.0, 3.0]	2.1 [2.0, 2.7]	2.4 [2.0, 3.0]	0.80
Intra-op transfusion, n (%)	1 (2)	3 (9)	0 (0)	<0.01
Intra-op complication, n (%)	2 (4)^b	0 (0)	2 (2)^c	0.34

Percent cases for each individual surgeon.

Injuries to tail of pancreas and to liver.

Injuries to bowel and gallbladder.

Bold indicates statistically significant values.

EBL = estimated blood loss; IVF = intravenous fluids.

Continuing aspirin was associated with significantly higher overall 30-day (p = 0.03) and Clavien 3 to 4 complications (p = 0.02), but similar Clavien 1 to 2 complications (p = 0.21; Table 4). The only cardiovascular complication of the entire cohort was bradycardia requiring pacemaker placement in a patient who continued aspirin. The most frequent nonbleeding complications for patients who continued aspirin were hypoxia from obstructive sleep apnea, pneumonia, or pneumothorax (cumulative: 6.1%). No patients suffered from urine leak and there were no deaths within 30 days.

Table 4.

Postoperative Complications of Patients by Perioperative Aspirin (American Society of Anesthesiologists) Administration Status

	Continued ASA (n = 49)	Held ASA (n = 34)	No prior ASA (n = 131)	p-Value
LOS, days (median [IQR])	1 [1, 2]	1 [1, 2]	1 [1, 2]	0.19
Bleeding complications, n (%)^a	13 (27)	5 (15)	18 (14)	0.13
Hemoglobin drop >3 g	12 (24)	5 (15	18 (14)	0.24
Transfusion	2 (4)	1 (3)	2 (1.5)	0.43
IR embolization^b	3 (6)	1 (3)	1 (0.8)	0.07
30-day complications, n (%)^c	12 (24)	4 (12)	10 (8)	0.03
Clavien 1–2	7 (14)	2 (6%)	8 (6)	0.21
Wound infection			1 (0.8)
Urinary tract infection		1 (3)	1 (0.8)
Fever			1 (0.8)
Atelectasis	1 (2)	1 (3)	1 (0.8)
Pneumonia	1 (2)
Pneumothorax	1 (2)
Hypoxia	1 (2)
Ileus			2 (1.5)
Transfusion	2 (4)		2 (1.5)
Retroperitoneal hematoma	1 (2)
Clavien 3–4 (%)	5 (10)	2 (6)	2 (1.5)	0.02
IR embolization	3 (6)	1 (3)	1 (0.8)
IR pneumothorax drainage			1 (0.8)
Pacemaker insertion	1 (2)
Reoperation for incisional hernia	1 (2)
Altered mental status (ICU)		1 (3)

Includes Hgb drop, postoperative transfusion, and IR embolization, which may overlap.

Continued ASA group had one embolization during hospitalization and two embolizations, which occurred after discharge. Held ASA and Control groups had embolizations that occurred during hospitalization.

There were no 30-day cardiovascular/thromboembolic complications or mortality rate in any group.

Bold indicates statistically significant values.

ICU = intensive care unit; IR = interventional radiology; LOS = length of stay.

Patients who continued aspirin incurred similar overall bleeding complications compared with those who held or never took aspirin (p = 0.13), with similar rates of hemoglobin drop >3 g/dL (p = 0.24), similar need for postoperative blood transfusion (p = 0.43), and nonsignificant trend to higher rate of IR embolization (p = 0.07) (Table 4). None of 20 patients who held additional anticoagulation experienced bleeding complications. Of patients who continued aspirin and required subsequent IR embolization, 1 (2.0%) occurred during the initial hospitalization on postoperative day (POD) 1 after hemodynamic instability accompanied by brisk sanguineous output from abdominal drain, while 2 (4.1%) occurred during readmission on PODs 21 and 30, respectively. Of these two delayed bleeds, one patient presented with abdominal pain and hemodynamic instability, while another presented with hematuria and clot retention. IR embolization for each patient who held or never took aspirin (n = 2) occurred during initial hospitalization on POD 0.

After controlling for comorbidity and surgical complexity on multivariable logistic regression, overall bleeding complications were not associated with holding aspirin (odds ratio [OR] 1.24; 95% confidence interval [CI] 0.38, 3.99; p = 0.72) or continuing aspirin (OR 2.12; 95% CI 0.78, 5.77; p = 0.14) in the perioperative period, when compared with never taking aspirin (Table 5). Patients requiring IR embolization had RENAL nephrometry scores of 7, 9, 10, 11, and 11. Median RENAL score was 10 [9–11] for patients requiring IR embolization compared with 7 [5–9] for patients who did not require IR embolization (p < 0.01; Table 6).

Table 5.

Multivariate Analysis of Predictors for Overall Bleeding Complications

	Odds ratio	95% confidence interval	p-Value
CCI^a	1.15	0.93, 1.41	0.18
RENAL nephrometry score^a	1.10	0.91, 1.34	0.30
Aspirin Status Categories^b
Held Aspirin	1.24	0.38, 3.99	0.72
Continued Aspirin	2.12	0.78, 5.77	0.14

Per unit increase.

Referent group: no prior aspirin.

Table 6.

Tumor Characteristics of Patients Requiring Interventional Radiology Embolization

	No IR embolization (n = 209)	IR embolization (n = 5)	p-Value
Median RENAL score	7 [5–9]	10 [9–11]	0.01
RENAL score categories, n (%)			0.03
Low (4–6)	84 (45)	0
Medium (7–9)	75 (41)	2 (40)
High (10–12)	26 (14)	3 (60)

Bold indicates statistically significant values.

Discussion

We demonstrate that continuing perioperative aspirin was not associated with significantly higher bleeding complications. To our knowledge, this series evaluates the largest group of patients continuing aspirin for partial nephrectomy to date. Our results suggest that compared with patients holding or not taking aspirin, patients continuing aspirin have (1) more baseline comorbidity and overall complications, (2) comparable risk of bleeding after controlling for comorbidity and surgical complexity, and (3) low overall rate of cardiovascular/thromboembolic complications.

Randomized controlled trials assessing continuation of aspirin for lower risk urologic procedures, including transrectal prostate biopsy²⁰ and transurethral prostatectomy,²¹ have shown an unchanged rate of transfusion and overall bleeding complications. Continuation of aspirin for emergent renal biopsies did not result in significantly increased major bleeding (5.2% vs 3.4%, p = 0.17) in a review of 1120 renal biopsies.²² Two recent series assessing 137 and 38 patients undergoing prostatectomy on aspirin showed significantly increased blood transfusion rate for open (21% vs 8%, p < 0.01), but not robotic, prostatectomy (0% vs 1%, p = 0.06; 5.3% vs 0%, p = 0.11) compared with patients not taking aspirin.^23,24

Prior evidence for bleeding risk for partial nephrectomy is primarily from three studies, which assessed outcomes for 6, 14, and 17 patients continuing aspirin.^13
–15 Althaus et al. studied 6 patients continuing aspirin, finding that one who restarted aspirin and warfarin developed delayed bleeding on POD 14, which resolved spontaneously.¹³ Parikh et al.¹⁵ compared 14 patients continuing aspirin with 12 who held aspirin and found no significant difference in transfusions or blood loss between groups. Leavitt et al.¹⁴ most recently compared 17 patients continuing aspirin with 84 patients holding aspirin. They found no significant differences in all bleeding complications between groups, with two patients (12%) who continued aspirin requiring transfusion and one (6%) patient continuing aspirin requiring IR embolization.

In our overall cohort, including 49 patients continuing aspirin, 10% required blood transfusion or embolization, similar to rates in prior series.¹⁴ In this study, we utilized a composite endpoint for overall bleeding complications incorporating drop in hemoglobin, transfusion, and/or embolization. It is important to note that univariate analysis showed nonsignificant but notably higher rate of bleeding complications in patients who continued aspirin, and a larger sample size may impact these results. However, multivariable analysis controlling for baseline comorbidity and surgical complexity corroborated that holding or continuing aspirin was not significantly associated with overall bleeding complications.

There was a nonsignificantly increased rate of IR embolization in patients continuing aspirin (6%) compared with the other groups. A lower baseline rate of IR embolization or surgical control of bleeding (2.5%) in a prior large series of 771 patients undergoing laparoscopic partial nephrectomy maintains the question of an association between aspirin and IR embolization.²⁵ Univariate analysis suggests an association between surgical complexity and need for IR embolization demonstrated by a significantly increased rate of high nephrometry scores in patients with vs without embolization (60% vs 14%, p < 0.03). A series assessing risk factors for the formation of symptomatic pseudoaneurysms following open partial nephrectomy found tumor complexity measured by PADUA score to be an independent risk factor (OR 1.9; 95% CI 1.29, 2.97; p < 0.001).²⁶ While the largest series to date of IR embolization following minimally invasive partial nephrectomies have not rigorously assessed surgical risk factors,²⁷ some studies have suggested central tumor location as a predictor for need for embolization.²⁸ Interestingly, we noted that the only two delayed bleeds requiring IR embolization on POD 21 and POD 30 occurred for patients who continued aspirin. While there are a limited number of events, this raises the possibility of aspirin resulting in unique alterations in arterial healing with subsequent delayed bleeding.

Continuing aspirin is primarily to prevent thromboembolic complications resulting from perioperative cessation.^5
–7 In our series, patients continuing aspirin were older and had higher overall CCI and increased specific vascular comorbidities compared with other groups. However, the rate of thromboembolic or cardiovascular events in our entire series is quite low (0.47%) compared with rates in prior studies (1.0%–7.7%).^14,15 The only cardiac complication that occurred in a patient continuing aspirin (bradycardia requiring pacemaker insertion) is arguably independent of anticoagulation. Although while we do not follow a standardized algorithm for which patients continue aspirin, our overall approach of continuing antiplatelet medications was highly effective in minimizing thrombotic and cardiovascular complications. Therefore, we recommend our practice of close consultation with an anesthesia clinic preoperatively and to generally only hold aspirin in low-risk patients who are taking the medication for primary prevention of cardiovascular disease.

The overall low rate of prior systemic anticoagulation with warfarin or rivaroxaban (3.7%) and routine inpatient postoperative administration of prophylactic subcutaneous heparin may be factors for zero postoperative DVTs or PEs in our population. Kefer et al. used a case-matched series of 47 patients with chronic anticoagulation undergoing open or laparoscopic partial nephrectomy. Their anticoagulation group had 26 (55%) patients on chronic warfarin, and this subset of patients had a 4.3% rate of PE.²⁹ A large series of 2473 patients who underwent renal surgery had 172 (7.0%) patients on chronic warfarin, clopidogrel, enoxaparin, or tinzaparin, and showed a 0.04% overall rate of DVT/PE and 0.2% MI.³⁰

There are several limitations to this study. There were heterogeneous indications for antiplatelet therapy, from history of prior thromboembolic events to primary prevention. While CCI reflected overall comorbidity, it was not a specific measure for bleeding or thromboembolic risk. Retrospective analysis and lack of randomization likely resulted in selection bias for holding aspirin based on tumor size, tumor location, and predicted surgical complexity. There may have been different utilization of hemostatic agents based on concern for or true increased intraoperative bleeding following aspirin administration. Due to almost all patients in our series undergoing combined arterial and venous clamping, conclusions regarding the continuation of aspirin for arterial clamped or off-clamp partial nephrectomy cannot be made. Although our sample size is significantly larger than prior series, there were too few bleeding events to allow a more comprehensive multivariable analysis incorporating more covariates or a less generalized composite endpoint. Finally, a larger sample size may have shown significant differences in bleeding complications between groups, highlighting the need for larger future studies.

Conclusions

Using a series with the largest cohort of patients continuing perioperative aspirin for RPN, we demonstrate that despite higher baseline comorbidity, patients continuing aspirin did not incur significantly greater bleeding complications, although there was a trend toward a higher rate of IR embolization. Further large studies are needed to confirm our findings and to ultimately develop a standardized perioperative antiplatelet protocol in this population.

Footnotes

Author Disclosure Statement

No competing financial interests exist.

Abbreviations Used

References

Gupta

, Streiff

, Resar

, Schoenberg

. Coronary stent management in elective genitourinary surgery. BJU Int, 2012; 110:480–484.

Naspro

, Rossini

, Musumeci

, Gadda

, Pozzo

LFD

. Antiplatelet therapy in patients with coronary stent undergoing urologic surgery: Is it still no man's land?. Eur Urol, 2013; 64:101–105.

Burger

, Chemnitius

J-M

, Kneissl

, Rücker

. Low-dose aspirin for secondary cardiovascular prevention—Cardiovascular risks after its perioperative withdrawal versus bleeding risks with its continuation— Review and meta-analysis. J Intern Med, 2005; 257:399–414.

Devereaux

, Mrkobrada

, Sessler

, et al. Aspirin in patients undergoing noncardiac surgery. N Engl J Med, 2014; 370:1494–1503.

Biondi-Zoccai

GGL

, Lotrionte

, Agostoni

, et al. A systematic review and meta-analysis on the hazards of discontinuing or not adhering to aspirin among 50,279 patients at risk for coronary artery disease. Eur Heart J, 2006; 27:2667–2674.

Maulaz

, Bezerra

, Michel

, Bogousslavsky

. Effect of discontinuing aspirin therapy on the risk of brain ischemic stroke. Arch Neurol, 2005; 62:1217–1220.

Poller

, Thomson

. Evidence for “rebound” hypercoagulability after stopping anticoagulants. Lancet Lond Engl, 1964; 2:62–64.

Fleisher

, Fleischmann

, Auerbach

, et al. 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: Executive summary: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation, 2014; 130:2215–2245.

Smith

, Feldman

, Hirshfeld

, et al. ACC/AHA/SCAI 2005 guideline update for percutaneous coronary intervention: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/SCAI Writing Committee to Update 2001 Guidelines for Percutaneous Coronary Intervention). Circulation, 2006; 113:e166–e286.

10.

Culkin

, Exaire

, Green

, et al. Anticoagulation and antiplatelet therapy in urological practice: ICUD/AUA review paper. J Urol, 2014; 192:1026–1034.

11.

Tanagho

, Kaouk

, Allaf

, et al. Perioperative complications of robot-assisted partial nephrectomy: Analysis of 886 patients at 5 United States centers. Urology, 2013; 81:573–579.

12.

Campbell

, Novick

, Belldegrun

, et al. Guideline for management of the clinical T1 renal mass. J Urol, 2009; 182:1271–1279.

13.

Althaus

, Dovirak

, Chang

, Taylor

, O'Halloran

, Wagner

. Aspirin and clopidogrel during robotic partial nephrectomy, is it safe?. Can J Urol, 2015; 22:7984–7989.

14.

Leavitt

, Keheila

, Siev

, et al. Outcomes of laparoscopic partial nephrectomy in patients continuing aspirin therapy. J Urol, 2015; 195:859–864.

15.

Parikh

, Toepfer

, Baylor

, Henry

, Berger

, Rukstalis

. Preoperative aspirin is safe in patients undergoing urologic robot-assisted surgery. J Endourol, 2012; 26:852–856.

16.

Orvieto

, Chien

, Tolhurst

, et al. Simplifying laparoscopic partial nephrectomy: Technical considerations for reproducible outcomes. Urology, 2005; 66:976–980.

17.

Kutikov

, Uzzo

. The R.E.N.A.L. nephrometry score: A comprehensive standardized system for quantitating renal tumor size, location and depth. J Urol, 2009; 182:844–853.

18.

Antonelli

, Minervini

, Mari

, et al. TriMatch comparison of the efficacy of FloSeal versus TachoSil versus no hemostatic agents for partial nephrectomy: Results from a large multicenter dataset: Efficacy of hemostatics for partial nephrectomy. Int J Urol, 2015; 22:47–52.

19.

Dindo

, Demartines

, Clavien

P-A

. Classification of surgical complications: A new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg, 2004; 240:205–213.

20.

Giannarini

, Mogorovich

, Valent

, et al. Continuing or discontinuing low-dose aspirin before transrectal prostate biopsy: Results of a prospective randomized trial. Urology, 2007; 70:501–505.

21.

Nielsen

, Holm-Nielsen

, Jespersen

, Vinther

, Settgast

, Gram

. The effect of low-dose acetylsalicylic acid on bleeding after transurethral prostatectomy—A prospective, randomized, double-blind, placebo-controlled study. Scand J Urol Nephrol, 2000; 34:194–198.

22.

Mackinnon

, Fraser

, Simpson

, Fox

, Geddes

. Is it necessary to stop antiplatelet agents before a native renal biopsy?. Nephrol Dial Transplant, 2008; 23:3566–3570.

23.

Leyh-Bannurah

S-R

, Hansen

, Isbarn

, et al. Open and robot-assisted radical retropubic prostatectomy in men receiving ongoing low-dose aspirin medication: Revisiting an old paradigm?. BJU Int, 2014; 114:396–403.

24.

Mortezavi

, Hermanns

, Hefermehl

, et al. Continuous low-dose aspirin therapy in robotic-assisted laparoscopic radical prostatectomy does not increase risk of surgical hemorrhage. J Laparoendosc Adv Surg Tech A, 2013; 23:500–505.

25.

Gill

, Kavoussi

, Lane

, et al. Comparison of 1,800 laparoscopic and open partial nephrectomies for single renal tumors. J Urol, 2007; 178:41–46.

26.

Kriegmair

, Mandel

, Rathmann

, Diehl

, Pfalzgraf

, Ritter

. Open partial nephrectomy for high-risk renal masses is associated with renal pseudoaneurysms: Assessment of a severe procedure-related complication. BioMed Res Int, 2015; 2015:981251.

27.

Ghoneim

, Thornton

, Solomon

, Adamy

, Favaretto

, Russo

. Selective arterial embolization for pseudoaneurysms and arteriovenous fistula of renal artery branches following partial nephrectomy. J Urol, 2011; 185:2061–2065.

28.

Nadu

, Kleinmann

, Laufer

, Dotan

, Winkler

, Ramon

. Laparoscopic partial nephrectomy for central tumors: Analysis of perioperative outcomes and complications. J Urol, 2009; 181:42–47; discussion 47.

29.

Kefer

, Desai

, Fergany

, Novick

, Gill

. Outcomes of partial nephrectomy in patients on chronic oral anticoagulant therapy. J Urol, 2008; 180:2370–2374; discussion 2734.

30.

Sfakianos

, Hakimi

, Kim

, et al. Outcomes in patients undergoing nephrectomy for renal cancer on chronic anticoagulation therapy. Eur J Surg Oncol, 2014; 40:1700–1705.