Mild hypothermia versus normothermia in patients undergoing cardiac surgery.

Objective: Temperature during cardiopulmonary bypass (CPB) for cardiac surgery has been controversial. The aim of the current study is to compare the outcomes for patients with mild hypothermia versus normothermic CPB temperatures. Methods: All patients who underwent cardiac surgery with CPB and temperatures ≥32°C from 2011 to 2018 were included, which consisted of mild hypothermia (32°C-35°C) and normothermia (>35°C) cohorts. Propensity matching (1:1) was performed for risk adjustment. Primary outcomes included operative and long-term survival. Secondary outcomes included postoperative complications. Results: A total of 6525 patients comprised 2 cohorts: mild hypothermia (32°C-35°C; n = 3148) versus normothermia (>35°C; n = 3377). Following adjustment for surgeon preference, there were 1601 propensity-matched patients who had similar baseline characteristics (standard mean difference, ≤0.10), including CPB time, crossclamp time, and intra-aortic balloon pump placement. Kaplan-Meier analysis showed no difference in long-term survival (82.6% vs 81.6%; P = .81). Over a median follow-up of 4.4 years, there were no differences in overall mortality (18.1% vs 18.1%; P = 1.1) or readmission (50.3% vs 48.3%; P = .2). Acute renal failure (3.7% vs 2.4%; P = .03) and intensive care unit hours (46.5 vs 45.1; P = .04) were significantly higher with hypothermia. There was no difference between cohorts for postoperative stroke (2.0% vs 2.0%; P = 1.0), reoperation (5.9% vs 6.0%; P = .9), or operative intra-aortic balloon pump placement (1.7% vs 1.8%; P = .9). Conclusions: Patients with mild hypothermia during CPB had increased postoperative renal failure and length of intensive care unit stay. Although there was no difference in long-term survival, mild hypothermia does not appear to offer patients appreciable benefits, compared with normothermia.

Permanent pacemaker placement following valve surgery is not independently associated with worse outcomes.

Background: Permanent pacemaker placement (PPM) is associated with morbidity following cardiac surgery. This study identified associations between PPM placement and 5-year outcomes for patients that require PPM following valvular surgery. Methods: All patients who underwent valvular surgery at our medical center from 2011 to 2018 were considered for analysis. Multivariable analysis identified associations between PPM placement, mortality, and readmissions. Primary outcomes were operative complications and mortality. Secondary outcomes included 5-year survival and readmission. Results: A total of 175 (4.86%) of 3602 valvular surgery patients required postoperative PPM. The PPM cohort had significantly worse baseline comorbidities, including greater Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) scores (3.8 vs 2.4 P < .0001). The PPM cohort had greater rates of blood product transfusion, prolonged ventilation, and new-onset atrial fibrillation. PPM placement was significantly associated with third-degree heart block (5.26; 95% confidence interval [95% CI], 1.00-27.53; P = .0496), ventricular fibrillation/tachycardia (3.90; 95% CI, 1.59-9.59; P = .01), and atrial fibrillation/flutter (1.53; 95% CI, 1.05-2.24; P = .03). On Kaplan-Meier estimates, 5-year survival (68.8% vs 83.1%; P = 01) was significantly reduced in the PPM cohort. Five-year all-cause readmission (60.4% vs 50.04%; P = .01) and heart failure readmission (35.5% vs 20.1%; P < .000) occurred more frequently in the PPM cohort. On multivariable Cox regression analysis, PPM placement (hazard ratio, 1.12; 95% CI, 0.84-1.50; P = .444) was not an independent predictor of mortality. On competing risk analysis, PPM (hazard ratio, 1.33; 95% CI, 0.99-1.80; P = .062) was not a predictor of hospital readmission. Conclusions: Valvular surgery patients who required postoperative PPM had elevated baseline operative risk. However, PPM implantation was not associated with mortality or readmission.

High-Risk Committee for Cardiac Surgery Decision-Making: Results From 110 Consecutive Patients.

BACKGROUND: This study evaluated our institutional experience in forming a surgeon-based committee to discuss and provide consensus opinion on high-risk cardiac surgical cases. METHODS: The committee consisted of 4 surgeons with at least 1 senior surgeon at any given time with a rotating schedule. Patients with a Society of Thoracic Surgeons predicted risk of mortality above specified thresholds were mandated for referral to the committee in addition to patients referred at the discretion of the surgeon. Kaplan-Meier analysis was used to model survival. RESULTS: A total of 110 consecutive patients were reviewed by the committee. The most common procedure types for referral were isolated coronary artery bypass grafting (47.3%; n = 52) and coronary artery bypass grafting with concomitant aortic valve replacement (19.1%; n = 21). The overall median Society of Thoracic Surgeons predicted risk of mortality for referred patients was 5.35% (interquartile range, 4.07%-7.89%). After group discussion, a total of 62 patients were recommended to proceed with surgery (56.4%). Reasons for declining surgery included consensus that an intervention was not indicated (39.6%; n = 19), that an alternative, nonsurgical procedure was recommended (29.2%; n = 14), that there was continued medical management and reevaluation (18.8%; n = 9), and that the patient was deemed at too high a risk for surgery (12.5%; n = 6). Operative mortality in patients proceeding with surgery was 4.6% (n = 2), with an observed-to-expected mortality of 0.86. The 6-month survival after surgery was 92.2%. CONCLUSIONS: Implementation of a surgeon-based committee to discuss high-risk cases provided a unified voice to referring physicians and facilitated consensus decision-making with acceptable clinical outcomes in a challenging patient cohort.

Outcomes in Patients With Severe Chronic Lung Disease Undergoing Index Cardiac Operations.

BACKGROUND: This study evaluated the impact of severe chronic lung disease on outcomes of index adult cardiac operations. METHODS: A single-center, retrospective study of adult patients with severe chronic lung disease (as defined by The Society of Thoracic Surgeons) undergoing index cardiac operations between 2010 and 2018 was performed. Multivariable Cox regression and Kaplan-Meier analyses were used to evaluate survival. RESULTS: Three hundred fifty-four patients (median age, 69 years; 32.77% women) were identified. Current smokers comprised 42.66% of the population, and 34.65% of patients required home oxygen. Median preoperative forced expiratory volume in 1 second was 48% of predicted (interquartile range, 41%-56%), and median diffusing capacity of the lungs for carbon monoxide was 78% of predicted (interquartile range, 55%-101%). Most patients underwent isolated coronary artery bypass (57.06%) or isolated aortic valve replacement (19.49%). Overall, 33 patients (9.07%) required a tracheostomy (median of 10 days from surgery) for a median of 49 days (interquartile range, 25-114) until decannulation. Preoperative home oxygen use was an independent predictor of 30-day (hazard ratio, 2.91; P = .030) and 1-year (hazard ratio, 2.12; P = .009) mortality. One-year and 5-year postoperative survival were 83.62% and 58.34%, respectively. CONCLUSIONS: Although severe chronic lung disease is a predictor of mortality and morbidity after index cardiac operations, only 9% of patients required a tracheostomy, and most were alive at 5 years after surgery. Home oxygen use may serve as a further stratification tool in this higher risk subset; however the presence of severe chronic lung disease alone should not deter from surgery in otherwise reasonable surgical candidates.

Left ventricular assist device implantation in patients with a history of malignancy.

BACKGROUND: This study evaluates the impact of a history of malignancy on outcomes of left ventricular assist device (LVAD) implantation. METHODS: Adult patients with a preimplant history of malignancy who underwent LVAD implantation between 2006 and 2018 were included. The primary outcome was post-LVAD survival. RESULTS: A total of 250 patients underwent LVAD implant during the study period, including 37 (14.8%) patients with a history of malignancy. Of these 37 patients, five (13.5%) had active malignancy at the time of LVAD implantation, and seven had more than one type of cancer. The median disease-free duration before LVAD was 3.5 years (interquartile range [IQR] 1.0-7.75 years). The most common types of malignancy included urologic (n = 20; 45.5%), skin (n = 7, 15.9%), and leukemia or lymphoma (n = 6; 13.6%). Median follow-up was 244 (IQR, 126-571) days and 313 (IQR 127-738) days for those with and without a history of malignancy, respectively (P = .49). Unadjusted post-LVAD survival was reduced in those with a malignancy history (2-year survival 53.4% vs 66.9%; P = .01), a finding that persisted after risk-adjustment (hazard ratio 1.89, 95% confidence interval, 1.13-3.14; P = .01). Only one (2.7%) patient died post-LVAD from their cancer. CONCLUSIONS: Although a history of malignancy is associated with reduced survival after LVAD implantation, more than half of the patients are alive at 2 years. This combined with the fact that most do not die from causes directly related to their cancer suggest that LVAD implantation is reasonable to perform in carefully selected patients with a history of malignancy.

Outcomes of tissue versus mechanical aortic valve replacement in patients 50 to 70 years of age.

BACKGROUND: Societal guidelines suggest that aortic valve replacement (AVR) in patients age 50 to 70 years can be performed with either bioprosthetic or mechanical valves. This study reviewed outcomes between these valve types among patients aged 50 to 70 years undergoing AVR. METHODS: We examined adult patients 50 to 70 years undergoing isolated AVR with a mechanical or bioprosthetic valve at a single institution between 2010 and 2018. Kaplan-Meier analysis was used to evaluate longitudinal survival and multivariable Cox regression analysis was used for risk adjustment. A propensity-matched analysis was performed as well. RESULTS: A total of 723 patients underwent isolated AVR with 467 (64.6%) receiving a bioprosthetic valve. At baseline, patients undergoing bioprosthetic AVR were older (median 65 vs 60 years; P < .001). One-year survival was comparable, however, survival at 5 years was significantly higher among patients undergoing mechanical AVR (95.5% vs 82.6%; P = .010). Among the 196 matched pairs, bioprosthetic AVR was associated with an increased adjusted hazard for death (hazards ratio, 3.29; P < .001). Additionally, 5-year freedom from stroke and bleeding were similar following matching, though mechanical AVR was associated with a greater freedom from repeat valve intervention (97.5% vs 92.9%; P = .020). CONCLUSION: In patients age 50 to 70, mechanical AVR is associated with improved long-term survival and freedom from repeat aortic valve intervention. Further large cohort studies should be performed to explore the potential benefits of mechanical valve replacement in this age range.

Outcomes of left ventricular assist device implantation in hypercoagulable patients.

BACKGROUND: The aim of this study was to evaluate outcomes of left ventricular assist devices (LVADs) in patients who tested positive for hypercoagulable hematologic disorders. METHODS: Adults undergoing continuous-flow LVAD implantation with preoperative hypercoagulability testing between 2004 and 2018 at a single center were reviewed. Hypercoagulability was defined as testing positive for antiphospholipid antibody, anticardiolipin antibody, lupus anticoagulant, protein C, protein S, factor V Leiden, and/or heparin-induced thrombocytopenia. The primary outcome was survival on the original LVAD. Secondary outcomes included rates of thromboembolic complications and readmission for intravenous heparin treatment. RESULTS: A total of 270 LVAD patients with pre-implant hypercoagulability testing were included, and 157 (58%) tested positive for a hypercoagulable disorder. Of those testing positive, 10 (6.4%) had a clinical pre-LVAD history of thromboembolic events. Survival was comparable between hypercoagulable and non-hypercoagulable patients (1 year: 73.3% vs 78.9%, P = .2195, 2-year: 60.7% vs 62.8%, P = .3627). Rates of pump thrombosis (14.0% vs 13.3%, P = .8618), hemolysis (4.5% vs 3.5%, P = .3536), stroke (18.5% vs 14.2%, P = .3483) and readmission for IV heparin therapy (87.3% (n = 137) vs 77.9% (n = 88), P = .7560) were similar. Outcomes were comparable in patients with positive hypercoagulable tests when stratified by pre-implant clinical history of hypercoagulability as well as stratified by recent preoperative exposure to heparin or warfarin. CONCLUSIONS: In this series, positive laboratory tests for hypercoagulability were common amongst patients undergoing LVAD implantation although few had positive clinical histories. Survival and freedom from thromboembolic complications were comparable to non-hypercoagulable patients. Hypercoagulability alone should therefore not serve as a contraindication to LVAD implantation.

DESE: estimating driver tissues by selective expression of genes associated with complex diseases or traits.

The driver tissues or cell types in which susceptibility genes initiate diseases remain elusive. We develop a unified framework to detect the causal tissues of complex diseases or traits according to selective expression of disease-associated genes in genome-wide association studies (GWASs). This framework consists of three components which run iteratively to produce a converged prioritization list of driver tissues. Additionally, this framework also outputs a list of prioritized genes as a byproduct. We apply the framework to six representative complex diseases or traits with GWAS summary statistics, which leads to the estimation of the lung as an associated tissue of rheumatoid arthritis.