Publications by authors named "O Wayne Isom"

153 Publications

Survival after Aortic Valve Replacement for Aortic Regurgitation: Prediction from Preoperative Contractility Measurement.

Cardiology 2018 23;140(4):204-212. Epub 2018 Aug 23.

Department of Cardiothoracic Surgery, Weill Medical College of Cornell University, New York, New York, USA.

Background: Noninvasive measurement of myocardial contractility (end-systolic wall stress-adjusted change in left ventricular ejection fraction from rest to exercise [ΔLVEF - ΔESS]) predicts heart failure, subnormal LVEFrest, and sudden death in asymptomatic patients with chronic severe aortic regurgitation (AR). Here we assess the relation of preoperative ΔLVEF - ΔESS to survival after aortic valve replacement (AVR).

Methods: Patients who underwent AVR for chronic, isolated, pure severe AR (n = 66) were followed for 13.0 ± 6.4 event-free years. Preoperative ΔLVEF - ΔESS (from combined echocardiographic and radionuclide cineangiographic data) enabled cohort stratification into 3 terciles (-1 to -11% [normal or mild] contractility deficit, -12 to -16% [moderate], and ≤-17% [severe], identical with segregation in our earlier study) to relate preoperative contractility to postoperative survival and to age- and gender-matched US census data.

Results: Since AVR, 22 patients died (average annual risk [AAR] for all-cause mortality for the entire co hort = 3.15%). Preoperative ΔLVEF - ΔESS predicted postoperative survival (p = 0.009, log rank test). By contractility terciles, all-cause AARs were 1.44, 2.58, and 6.40%. Survival was lower than among US census comparators (p < 0.02), but the "mild" tercile was indistinguishable from census data (p = ns). By multivariable Cox regression, survival prediction by pre-AVR ΔLVEF - ΔESS was independent of, and superior to, prediction by age at surgery, gender, preoperative functional class, LVEFrest, LVEFexercise, change in LVEFrest to exercise, and LV diastolic or systolic dimensions (p ≤ 0.01, pre-AVR ΔLVEF - ΔESS vs. other covariates).

Conclusion: In severe AR, preoperative contractility predicts post-AVR survival and may be prognostically superior to clinical, geometric and performance descriptors, potentially impacting on patient selection for surgery.
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October 2019

National trends in utilization and in-hospital outcomes of mechanical versus bioprosthetic aortic valve replacements.

J Thorac Cardiovasc Surg 2015 May 11;149(5):1262-9.e3. Epub 2015 Feb 11.

Department of Healthcare Policy and Research, Weill Cornell Medical College, New York, NY. Electronic address:

Objective: Substantial controversy surrounds the choice between a mechanical versus bioprosthetic prosthesis for aortic valve replacement (AVR), based on age. This study aims to investigate national trends and in-hospital outcomes of the 2 prosthesis choices.

Methods: All patients aged >18 years in the National Inpatient Sample who received an AVR between 1998 and 2011 were considered. Valve-type use was examined by patient, procedural, and hospital characteristics, after which we matched patients based on their propensity score for receiving a bioprosthetic valve and compared their in-hospital outcomes.

Results: Bioprosthetic valves comprised 53.3% of 767,375 implanted valves, an increase in use from 37.7% in the period 1998 to 2001 to 63.6% in the period 2007 to 2011. The median age was 74 years for patients receiving bioprosthetic valves, and 67 years for those receiving mechanical valves. Use of bioprosthetic valves increased across all age groups, most markedly in patients age 55 to 64 years. Compared with patients receiving mechanical valves, these patients had a higher incidence of renal disease (8.0% vs 4.2%), coronary artery disease (58.5% vs 50.5%), concomitant coronary artery bypass grafting (46.7% vs 41.9%), and having surgery in a high-volume (>250 cases per year) center (31.3% vs 18.5%). Patients receiving bioprosthetic valves had a higher occurrence of in-hospital complications (55.9% vs 48.6%), but lower in-hospital mortality (4.4% vs 4.9%) than patients receiving mechanical valves. This difference was confirmed in propensity-matched analyses (complications: 52.7% vs 51.5%; mortality: 4.3% vs 5.2%).

Conclusions: Use of bioprosthetic valves in AVR increased dramatically from 1998 to 2011, particularly in patients age 55 to 64 years. Prosthesis selection varied significantly by facility, with low-volume facilities favoring mechanical valves. Aortic valve replacement with a bioprosthetic valve, compared with a mechanical valve, was associated with lower in-hospital mortality.
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May 2015

Preoperative hypothyroidism is a risk factor for postoperative atrial fibrillation in cardiac surgical patients.

J Card Surg 2015 Apr 2;30(4):307-12. Epub 2015 Feb 2.

Department of Cardiothoracic Surgery, New York Methodist Hospital, Brooklyn, New York; Department of Cardiothoracic Surgery, New York Presbyterian Hospital/Weil Cornell Medical Center, New York City, New York.

Background And Aim: Although studies analyzing the effect of thyroid supplementation on postoperative morbidity and mortality from cardiac surgery have been inconclusive, they suggest a role in the prevention of postoperative atrial fibrillation. To further explore this relationship we conducted a retrospective study to determine whether abnormalities in routine preoperative thyroid function studies correlate with the incidence of postoperative atrial fibrillation.

Methods: From May 2004 until July 2011, 821 patients with complete thyroid function testing performed preoperatively underwent cardiac surgery. Preoperative, intraoperative, and postoperative laboratory, clinical and hemodynamic data including postoperative electrocardiogram monitoring were retrospectively evaluated.

Results: Mean age was 65.7 years and 36% (294) of patients were female. Mean preoperative ejection fraction was 48.6% and 18% (100) had clinical heart failure. Ninety percent (682) of patients were euthyroid and 10% (77) were hypothyroid. Atrial fibrillation occurred significantly more frequently in hypothyroid patients (33.4% vs. 22.5%; p = .033). In multivariable analysis, increasing thyroid stimulating hormone (TSH) level (OR: 1.11; CI: 1.01 to 1.22; p = .030) was an independent predictor of postoperative atrial fibrillation. Beta blocker use within 24 hours prior to operation was protective (OR: .54; CI: .35 to .83; p = .005). Length of stay was significantly longer in patients with postoperative atrial fibrillation (9.1 vs. 6.5 days; p < .001).

Conclusions: In the current study, preoperative hypothyroidism was associated with postoperative atrial fibrillation. Further studies are warranted to delineate whether preoperative hypothyroidism is a useful biomarker for selecting patients most likely to benefit from preoperative thyroid supplementation in the prevention of postoperative atrial fibrillation.
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April 2015

Comparative effectiveness of robotic-assisted vs thoracoscopic lobectomy.

Chest 2014 Dec;146(6):1505-1512

Department of Public Health, New York Presbyterian Hospital-Weill Cornell Medical College, New York, NY.

Background: Robotic-assisted lobectomy is being offered increasingly to patients. However, little is known about its safety, complication profile, or effectiveness.

Methods: Patients undergoing lobectomy in in the United States from 2008 to 2011 were identified in the Nationwide Inpatient Sample. In-hospital mortality, complications, length of stay, and cost for patients undergoing robotic-assisted lobectomy were compared with those for patients undergoing thoracoscopic lobectomy.

Results: We identified 2,498 robotic-assisted and 37,595 thoracoscopic lobectomies performed from 2008 to 2011. The unadjusted rate for any complication was higher for those undergoing robotic-assisted lobectomy than for those undergoing thoracoscopic lobectomy (50.1% vs 45.2%, P < .05). Specific complications that were higher included cardiovascular complications (23.3% vs 20.0%, P < .05) and iatrogenic bleeding complications (5.0% vs 2.0%, P < .05). The higher risk of iatrogenic bleeding complications persisted in multivariable analyses (adjusted OR, 2.64; 95% CI, 1.58-4.43). Robotic-assisted lobectomy costs significantly more than thoracoscopic lobectomy ($22,582 vs $17,874, P < .05).

Conclusions: In this early experience with robotic surgery, robotic-assisted lobectomy was associated with a higher rate of intraoperative injury and bleeding than was thoracoscopic lobectomy, at a significantly higher cost.
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December 2014

Gastrointestinal complications after mitral valve surgery.

Ann Thorac Cardiovasc Surg 2014 4;20(4):292-8. Epub 2013 Jun 4.

Department of Cardiothoracic Surgery, New York Presbyterian Hospital, Weill Cornell Medical College, New York, USA.

Introduction: Gastrointestinal (GI) complications are well-recognized risks of open heart surgery. However, open heart surgery comes in different shapes and sizes with widely varying pre-operative, intra-operative and post-operative pathologies. The aim of this study was to examine the etiology and risk factors for GI complications after mitral valve surgery.

Methods: A retrospective analysis of 565 patients who underwent mitral valve surgery from 2003-2005 was performed. Prospectively collected data included preoperative risk factors, cardiac status, intra-operative data, postoperative GI complications and mortality. Survival was analyzed using log-rank analysis.

Results: In this study population, 13 patients (2.3%) had 16 GI complications after mitral valve surgery resulting in an overall mortality of 0.7%. Complications included GI bleed (n = 9), cholecystitis (n = 3), perforated diverticulitis (n = 1) and ischemic bowel (n = 3). By univariate analysis, a history of hypertension, chronic renal insufficiency (CRI), hypercholesterolemia, myocardial infarction, congestive heart failure, cardiogenic shock, emergency valve surgery, coronary artery bypass surgery and preoperative vasopressor use were each associated with an increased incidence of GI complications (p <0.05). No increased incidence was seen in patients with atrial fibrillation. On multivariate analysis adjusted for age, cardiogenic shock (OR 8.1; 95% CI, 1.9-34.8), CRI (OR 8.1; 95% CI, 2.2-30.0) and vasopressor use (OR 6.5; 95% CI, 1.3-31.0) remained significant (p <0.02). Mean survival (3.2 vs. 5.4 years) was significantly lower (p <0.05) in those with GI complications.

Conclusions: GI complications after mitral valve surgery are infrequent, with a higher incidence in those with cardiogenic shock, CRI or requiring vasopressors. Pre-operative hemodynamic instability may be a bellwether for potential GI complications and should be of more prominent concern in this cohort of patients.
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May 2015