Eric L. Sarin

Impact of preoperative renal dysfunction on long-term survival for patients undergoing aortic valve replacement.

BACKGROUND The impact of the degrees of renal dysfunction (RD) after aortic valve replacement (AVR) has not been well described. The purpose of this study was to compare patients undergoing AVR with a range of renal function from normal to dialysis-dependence. METHODS A retrospective review of 2,408 patients undergoing AVR with or without coronary artery bypass graft surgery (CABG) from January 1996 to March 2009 was performed. Glomerular filtration rate (GFR) was estimated for patients using the Modification of Diet in Renal Disease formula. Multivariable logistic and Cox regression methods were used to determine the independent association of GFR with outcomes. Adjusted odds ratios were calculated for in-hospital outcomes, and Kaplan-Meier curves were created to estimate long-term survival. RESULTS In all, 1,512 patients (62.8%) had isolated AVR, and 896 (37.2%) underwent AVR plus CABG. Preoperative RD was common among all patients: 1,148 of 2,408 (47.7%) with mild RD (GFR 60 to 90 mL·min(-1)·1.73 m(-2)), 644 of 2,408 (26.7%) moderate RD (GFR 30 to 59 mL·min(-1)·1.73 m(-2)), 59 of 2,408 (2.5%) severe RD (GFR 15 to 30 mL·min(-1)·1.73 m(-2)), and 114 (4.7%) with kidney failure (GFR<15) or requiring dialysis. In-hospital mortality generally rose with RD, from 2.9% for patients with no RD to 15.8% for patients with severe RD, and 17.3% for patients requiring dialysis. Patients with severe RD or preoperative dialysis were associated with significantly poorer outcomes. Adjusted long-term survival is progressively worse across levels of RD, as was postoperative length of stay (p<0.001). CONCLUSIONS Preoperative RD is common among the AVR population and is associated with diminished long-term survival. The association between RD and worse outcomes after AVR surgery has significant clinical implications.

Aortic Valve Replacement for Aortic Stenosis in Patients With Left Ventricular Dysfunction

BACKGROUND The purpose of this study was to assess the impact of left ventricular dysfunction and other risk factors on short- and mid-term outcomes after aortic valve replacement for aortic stenosis. METHODS From January 1, 2002, to December 31, 2007, 773 consecutive patients underwent primary aortic valve replacement for aortic stenosis at a single institution; concomitant coronary artery bypass graft surgery (CABG) was performed in 45.4% (351 of 773). Multivariable regression analysis was used to identify predictors of in-hospital mortality, with ejection fraction (EF) as the primary variable of interest. After discharge, survival status was determined using the Social Security Death Index. A Cox proportional hazards regression model was used to identify predictors of mid-term mortality. RESULTS On univariable analysis, EF (odds ratio [OR] 0.979, 95% confidence interval [CI]: 0.960 to 0.999, p = 0.044) but not concomitant CABG emerged as a predictor of in-hospital mortality. However, on multivariable analysis, neither EF nor concomitant CABG was associated with increased in-hospital mortality. Multivariable predictors of in-hospital mortality included age, emergent status, and prolonged bypass time. On univariable analysis, mid-term mortality was associated with EF and concomitant CABG (OR 0.979, 95% CI: 0.966 to 0.991, p = 0.001, and OR 1.61, 95% CI: 1.11 to 2.36, p = 0.013, respectively). However, after multivariable adjustment, only EF was associated with mid-term mortality (adjusted OR 0.985, 95% CI: 0.970 to 1.00, p = 0.049). Other multivariable predictors of mid-term mortality included age, dialysis-dependent renal failure, previous stroke, and peripheral vascular disease. CONCLUSIONS Left ventricular dysfunction, in addition to other patient comorbidities, may negatively impact survival after aortic valve replacement. Careful consideration of the cumulative effect of these multiple risk factors is necessary to optimize patient outcomes.

Transapical and Transaortic Transcatheter Aortic Valve Replacement in the United States

BACKGROUND When transcatheter aortic valve replacement (TAVR) cannot be carried out through transfemoral access, alternative access TAVR is indicated. The purpose of this study was to explore inhospital and 1-year outcomes of patients undergoing alternative access TAVR through the transapical (TA) or transaortic (TAo) techniques in the United States. METHODS Clinical records of 4,953 patients undergoing TA (n = 4,085) or TAo (n = 868) TAVR from 2011 to 2014 in The Society of Thoracic Surgeons (STS)/American College of Cardiology Transcatheter Valve Therapy Registry were linked to Centers for Medicare and Medicaid Services hospital claims. Inhospital and 1-year clinical outcomes were stratified by operative risk; and the risk-adjusted association between access route and mortality, stroke, and heart failure repeat hospitalization was explored. RESULTS Mean age for all patients was 82.8 ± 6.8 years. The median STS predicted risk of mortality was significantly higher among patients undergoing TAo (8.8 versus 7.4, p < 0.001). When compared with TA, TAo was associated with an increased risk of unadjusted 30-day mortality (10.3% versus 8.8%) and 1-year mortality (30.3% versus 25.6%, p = 0.006). There were no significant differences between TAo and TA for inhospital stroke rate (2.2%), major vascular complications (0.3%), and 1-year heart failure rehospitalizations (15.7%). Examination of high-risk and inoperable subgroups showed that 1-year mortality was significantly higher for TAo patients classified as inoperable (p = 0.012). CONCLUSIONS Patients undergoing TAo TAVR are older, more likely female, and have significantly higher STS predicted risk of mortality scores than patients operated on by TA access. There were no risk-adjusted differences between TA and TAo access in mortality, stroke, or readmission rates as long as 1 year after TAVR.

The Expanding Role of Endoscopic Robotics in Mitral Valve Surgery: 1,257 Consecutive Procedures

BACKGROUND The role of robotic instruments in mitral valve (MV) surgery continues to evolve. The purpose of this study was to assess the safety, efficacy, and scope of MV surgery using a lateral endoscopic approach with robotics (LEAR) technique. METHODS From 2006 to 2013, a dedicated LEAR team performed 1,257 consecutive isolated MV procedures with or without tricuspid valve repair or atrial ablation. The procedures were performed robotically through five right-side chest ports with femoral artery or ascending aortic perfusion and balloon occlusion. Operative videos and data were recorded on all procedures and reviewed retrospectively. RESULTS The mean age of all patients was 59.3 ± 20.5 years, and 8.4% (n = 105) had previous cardiac surgery. The MV repair was performed in 1,167 patients (93%). The MV replacement was performed in 88 patients (7%), and paravalvular leak repair in 2 patients. Concomitant atrial ablation was performed in 226 patients (18%), and tricuspid valve repair in 138 patients (11%). Operative mortality occurred in 11 patients (0.9%) and stroke in 9 patients (0.7%). Predischarge echocardiograms demonstrated mild or less mitral regurgitation in 98.3% of MV repair patients. At mean follow-up of 50 ± 26 months, 44 patients (3.8%) required MV reoperation. Application of the LEAR technique to all institutional isolated MV procedures increased from 46% in the first year to more than 90% in the last 3 years. CONCLUSIONS Mitral valve repair or replacement, including concomitant procedures, can be performed safely and effectively using the LEAR technique. With a dedicated robotic team, the vast majority of patients with MV disorders, either isolated or with concomitant problems, can be treated using the LEAR technique.

Temporal Changes in Interpapillary Muscle Dynamics as an Active Indicator of Mitral Valve and Left Ventricular Interaction in Ischemic Mitral Regurgitation

BACKGROUND Regional subpapillary myocardial hypokinesis may impair lateral reduction in the interpapillary muscle distance (IPMD) from diastole to systole, and adversely affect mitral valve geometry and tethering. OBJECTIVES The goal of this study was to investigate the impact of impaired lateral shortening in the interpapillary muscle distance on mitral valve geometry and function in ischemic heart disease. METHODS To quantify ventricular size/shape, regional myocardial contraction, lateral shortening of the IPMD, mitral valve geometry, and severity of mitral regurgitation, 67 patients with ischemic heart disease underwent cardiac magnetic resonance imaging, and a correlation analysis of measured parameters was performed. The impact of reduced IPMD shortening on mitral valve (dys)function was confirmed in swine and in a physiological computational mitral valve model. RESULTS Lateral shortening of the IPMD from diastole to systole was severely reduced in patients with moderate/severe ischemic mitral regurgitation (9.6 ± 2.8 mm), but preserved in mild IMR (11.5 ± 3.4 mm). Left ventricular size and ejection fraction did not differ between the groups. In swine with subpapillary infarction and impaired IPMD, mitral regurgitation was evident within 1 week, compared to those pigs with a nonpapillary infarction and preserved IPMD. In the controlled computational valve model, IPMD had the maximal impact on regurgitation, and was exacerbated with additional annular dilation. CONCLUSIONS By using cardiac magnetic resonance imaging in humans, we demonstrated that it is the impairment of lateral shortening between the papillary muscles, and not passive ventricular size, that governs the severity of mitral regurgitation. Loss of lateral shortening of IPMD tethers the leaflet edges and impairs their systolic closure, resulting in mitral regurgitation, even in small ventricles. Understanding the lateral dynamics of ventricular-valve interactions could aid the development of new repair techniques for ischemic mitral regurgitation.

Long-term survival for patients with preoperative renal failure undergoing bioprosthetic or mechanical valve replacement.

BACKGROUND The objective of this study was to assess short-term and long-term outcomes after valve replacement with biologic or mechanical prostheses in patients with preoperative end-stage renal disease on chronic dialysis. METHODS A retrospective review of patients with end-stage renal disease undergoing valve replacement from January 1996 through March 2008 at Emory Healthcare Hospitals was performed. Outcomes were compared using χ(2) tests and 2-sample t tests. Adjusted long-term survival up to 10 years was assessed with Kaplan-Meier plots and compared between biologic and mechanical replacements using the Cox proportional hazards model. RESULTS A total of 202 patients underwent 211 valve replacement operations. Patient age was 20 to 83 years (mean age, 54.8 ± 14.0); 115 of 211 (54.5%) were male. Operations included the following: 100 of 211 (47.4%) isolated aortic; 49 of 211 (23.2%) isolated mitral; 4 of 211 (1.9%) isolated tricuspid; and 58 of 211 (27.5%) combined replacements. Thirteen (6.2%) patients underwent reoperative valve replacements. Most patients received bioprosthetic valves (143 of 211, 67.8%), while 68 of 211 (32.2%) received mechanical valves. Concomitant coronary artery bypass was performed in 53 of 211 (25.1%) patients. Thirty-day mortality was in 42 of 211 patients (19.9%) and was not different between bioprosthetic and mechanical replacements. Overall 10-year survival was 18.1% for all patients and was not influenced by valve type implanted. CONCLUSIONS For patients with end-stage renal disease treated with dialysis, valve replacement carries acceptable operative mortality. Long-term survival is similar among patients receiving bioprosthetic versus mechanical valve replacement. Careful risk assessment and choice of valve prosthesis should be performed prior to surgical intervention in this high-risk patient population.

Short- and long-term outcomes in patients undergoing valve surgery with end-stage renal failure receiving chronic hemodialysis

OBJECTIVES The objective of this study was to evaluate the effect of chronic preoperative hemodialysis for end-stage renal failure in patients undergoing valve surgery. METHODS A retrospective review of patients undergoing primary valve with or without coronary artery bypass surgery from 1996 to 2008 at a US academic center was performed. The patients were divided into two groups: group 1 underwent valve surgery without preoperative dialysis (n = 5084) and group 2 underwent valve surgery with preoperative dialysis (n = 224). The outcomes were evaluated using multivariate regression analysis, and long-term survival was assessed with Kaplan-Meier plots. RESULTS The patients in group 2 were younger (P < .001), were more likely women (P = .04), and presented with New York Heart Association class III-IV (P < .001). The ejection fraction was similar between the two groups (P = .36). The adjusted perioperative morbidity was similar between the two groups for stroke (P = .79) and myocardial infarction (P = .68). Resource use (postoperative length of stay) was greater in group 2 (P < .001), as was in-hospital mortality (group 1, 263/5084 [5.2%] vs group 2, 41/224 [18.3%]; P < .001). The 1-, 5-, and 10-year survival was less in group 2 (P < .001); the median survival was 12 or more years in group 1 and 1.8 years in group 2. Preoperative end-state renal disease, among others, show a trend as an independent predictor for short-term mortality and was a significant predictor for long-term mortality. CONCLUSIONS In this large cohort of patients, preoperative dialysis conferred a high risk of perioperative morbidity and mortality and poor long-term survival after valve surgery. Risk stratification and future research efforts should focus on more precise identification of the benefits of valve surgery in this high-risk patient population.

Moderate Versus Deep Hypothermia With Unilateral Selective Antegrade Cerebral Perfusion for Acute Type A Dissection

BACKGROUND Despite improved results with surgical therapy for acute type A aortic dissection (ATAAD), there remains a lack of consensus regarding the optimal method of cerebral protection and circulation management during ATAAD. The purpose of this study is to determine whether in the setting of antegrade cerebral perfusion, moderate hypothermic circulatory arrest (MHCA) provides equivalent cerebral and visceral protection as deep hypothermic circulatory arrest (DHCA) for patients undergoing emergent ATAAD repair. METHODS A review of the Emory aortic surgery database from 2004 to 2014 identified 288 patients who underwent ATAAD with right axillary artery cannulation, unilateral selective antegrade cerebral perfusion (uSACP), and hypothermic circulatory arrest (HCA). In all, 88 patients underwent HCA at 24 °C or lower (DHCA), and 206 patients underwent HCA at more than 24 °C (MHCA). Major adverse outcomes of death, stroke, temporary neurologic dysfunction, and dialysis-dependent renal failure were examined. RESULTS The groups were well matched for age and major comorbidities. The DHCA patients underwent HCA at lower temperatures (DHCA 21.6 ± 3.1 °C vs MHCA 27.4 ± 1.6 °C, p < 0.01). There were no significant differences in cardiopulmonary bypass, cross-clamp, or HCA times. Mortality was 14.6% for DHCA patients, and 9.2% for MHCA patients (p = 0.17). There was no significant difference in stroke, temporary neurologic dysfunction, or dialysis-dependent renal failure. There was no association with either MHCA plus uSACP or DHCA plus uSACP and any of the major adverse outcomes (p > 0.05). CONCLUSIONS Moderate HCA with uSACP is an effective circulation management strategy that provides excellent cerebral and visceral protection during emergent ATAAD repair. In the setting of antegrade cerebral perfusion, deep hypothermia does not provide any additional benefit.

Outcomes for Transcatheter Aortic Valve Replacement in Nonagenarians.

BACKGROUND Transcatheter aortic valve replacement (TAVR) may offer extreme-aged patients a treatment alternative to surgical aortic valve replacement (SAVR). The objective of this study was to describe outcomes of TAVR in nonagenarians using transfemoral and alternative access techniques. METHODS In a retrospective review, we found 95 nonagenarians who underwent TAVR from September 2007 through February 2014 at Emory University using a balloon expandable valve: transfemoral (n = 66), transapical (n = 14), transaortic (n = 14), and transcarotid (n = 1). Morbidity and 30-day and midterm mortality were assessed. Kaplan-Meier plots were used to determine midterm survival rates. RESULTS The mean age of the patients was 91.8 ± 1.8 years, and 49 (52%) were female. Postoperative morbidity included 1 patient (1%) each with stroke, myocardial infarction, pneumonia, and renal failure. The mean postoperative length of stay was 6.8 ± 5.1 days for all patients. Overall 30-day mortality was 3.2%, much less than The Society of Thoracic Surgeons predicted risk of mortality of 14.5% ± 7.3%. There were no deaths in the transfemoral patients, but there were 2 transapical deaths (14.3%) and 1 transaortic death (7.1%). The Kaplan-Meier estimate of median survival was 2.6 years. CONCLUSIONS Extreme-aged nonagenarian patients may have excellent outcomes from TAVR at 30-day and midterm follow-up. Alternative access TAVR is associated with higher morbidity and mortality than transfemoral TAVR. Referral for TAVR of nonagenarians should not be precluded based on age alone.

Automated video-based assessment of surgical skills for training and evaluation in medical schools

PurposeRoutine evaluation of basic surgical skills in medical schools requires considerable time and effort from supervising faculty. For each surgical trainee, a supervisor has to observe the trainees in person. Alternatively, supervisors may use training videos, which reduces some of the logistical overhead. All these approaches however are still incredibly time consuming and involve human bias. In this paper, we present an automated system for surgical skills assessment by analyzing video data of surgical activities.MethodWe compare different techniques for video-based surgical skill evaluation. We use techniques that capture the motion information at a coarser granularity using symbols or words, extract motion dynamics using textural patterns in a frame kernel matrix, and analyze fine-grained motion information using frequency analysis.ResultsWe were successfully able to classify surgeons into different skill levels with high accuracy. Our results indicate that fine-grained analysis of motion dynamics via frequency analysis is most effective in capturing the skill relevant information in surgical videos.ConclusionOur evaluations show that frequency features perform better than motion texture features, which in-turn perform better than symbol-/word-based features. Put succinctly, skill classification accuracy is positively correlated with motion granularity as demonstrated by our results on two challenging video datasets.