Outcomes of Conventional Cardiac Surgery in Patients With Severely Reduced Ejection Fraction in the Modern Era

Identifying and mitigating risk of postcardiotomy cardiogenic shock in patients with ischemic and nonischemic cardiomyopathy

OBJECTIVES

To identify preoperative predictors of postcardiotomy cardiogenic shock in patients with ischemic and nonischemic cardiomyopathy and evaluate trajectory of postoperative ventricular function.

METHODS

From January 2017 to January 2020, 238 patients with ejection fraction <30% (206/238) or 30% to 34% with at least moderately severe mitral regurgitation (32/238) underwent conventional cardiac surgery at Cleveland Clinic, 125 with ischemic and 113 with nonischemic cardiomyopathy. Preoperative ejection fraction was 25 ± 4.5%. The primary outcome was postcardiotomy cardiogenic shock, defined as need for microaxial temporary left ventricular assist device, extracorporeal membrane oxygenation, or vasoactive-inotropic score >25. RandomForestSRC was used to identify its predictors.

RESULTS

Postcardiotomy cardiogenic shock occurred in 27% (65/238). Pulmonary artery pulsatility index <3.5 and pulmonary capillary wedge pressure >19 mm Hg were the most important factors predictive of postcardiotomy cardiogenic shock in ischemic cardiomyopathy. Cardiac index <2.2 L·min-1 m-2 and pulmonary capillary wedge pressure >21 mm Hg were the most important predictive factors in nonischemic cardiomyopathy. Operative mortality was 1.7%. Ejection fraction at 12 months after surgery increased to 39% (confidence interval, 35-40%) in the ischemic group and 37% (confidence interval, 35-38%) in the nonischemic cardiomyopathy group.

CONCLUSIONS

Predictors of postcardiotomy cardiogenic shock were different in ischemic and nonischemic cardiomyopathy. Right heart dysfunction, indicated by low pulmonary artery pulsatility index, was the most important predictor in ischemic cardiomyopathy, whereas greater degree of cardiac decompensation was the most important in nonischemic cardiomyopathy. Therefore, preoperative right heart catheterization will help identify patients with low ejection fraction who are at greater risk of postcardiotomy cardiogenic shock.

Predicting outcomes in patients with low ejection fraction undergoing coronary artery bypass graft

Introduction

Reduced left ventricular ejection fraction (LVEF) is a well-known predictor of adverse events after cardiac surgery. We aimed to assess the outcomes in patients with low LVEF undergoing coronary artery bypass graft.

Methods

In this retrospective cohort, we included all patients with left ventricular ejection fraction ≤ 40 who underwent coronary artery bypass grafting between March 2007 and March 2016 (with a median follow-up of nine years) at Tehran Heart Center. Demographics and clinical characteristics were extracted from the data registry. Akaike information criterion (AIC) was used. The univariate Cox regression was performed. We investigated the predictors of mortality and major adverse cardiac and cerebrovascular events (MACCE) using Cox multivariable regression.

Results

In total, 5,532 cases (79 % male) with a mean age of 65.58 were included in the study. The nine-year overall survival was calculated at 68 %, and more than half of the patients had MACCE (55 %). In adjusted multivariable Cox regression analysis, moderate to severe mitral valve regurgitation, glomerular filtration rate ≤ 60, mild right ventricular dysfunction, and valvular heart disease independently predicted higher mortality. The abovementioned predictors and peripheral vascular disease significantly increased MACCE.

Conclusion

Our study indicates the clinical significance of mitral regurgitation, valvular heart disease, and renal function in patients with low ejection fraction treated by coronary artery bypass grafting surgery. Identifying predictors of adverse events can help with clinical decision-making and risk stratification, ultimately improving patient outcomes.

Low Left-Ventricular Ejection Fraction as a Predictor of Intraprocedural Cardiopulmonary Resuscitation in Patients Undergoing Transcatheter Aortic Valve Implantation

Transcatheter aortic valve replacement (TAVR) has become an established alternative to surgical aortic valve replacement (AVR) for patients with moderate-to-high perioperative risk. Periprocedural TAVR complications decrease with growing expertise of implanters. Nevertheless, TAVR can still be accompanied by life-threatening adverse events such as intraprocedural cardiopulmonary resuscitation (CPR). This study analyzed the role of a reduced left-ventricular ejection fraction (LVEF) in intraprocedural complications during TAVR. Perioperative and postoperative outcomes from patients undergoing TAVR in a high-volume center (600 cases per year) were analyzed retrospectively with regard to their left-ventricular ejection fraction. Patients with a reduced left-ventricular ejection fraction (EF ≤ 40%) faced a significantly higher risk of perioperative adverse events. Within this cohort, patients were significantly more often in need of mechanical ventilation (35% vs. 19%). These patients also underwent CPR (17% vs. 5.8%), defibrillation due to ventricular fibrillation (13% vs. 5.4%), and heart-lung circulatory support (6.1% vs. 2.5%) more often. However, these intraprocedural adverse events showed no significant impact on postoperative outcomes regarding in-hospital mortality, stroke, or in-hospital stay. A reduced preprocedural LVEF is a risk factor for intraprocedural adverse events. With respect to this finding, the identified patient cohort should be treated with more caution to prevent intraprocedural incidents.

The Long-Term Impact of Diastolic Dysfunction After Routine Cardiac Surgery

OBJECTIVE

To determine the impact of diastolic dysfunction (DD) on survival after routine cardiac surgery.

DESIGN

This was an observational study of consecutive cardiac surgeries from 2010 to 2021.

SETTING

At a single institution.

PARTICIPANTS

Patients undergoing isolated coronary, isolated valvular, and concomitant coronary and valvular surgery were included. Patients with a transthoracic echocardiogram (TTE) longer than 6 months prior to their index surgery were excluded from the analysis.

INTERVENTIONS

Patients were categorized via preoperative TTE as having no DD, grade I DD, grade II DD, or grade III DD.

MEASUREMENTS AND MAIN RESULTS

A total of 8,682 patients undergoing a coronary and/or valvular surgery were identified, of whom 4,375 (50.4%) had no DD, 3,034 (34.9%) had grade I DD, 1,066 (12.3%) had grade II DD, and 207 (2.4%) had grade III DD. The median (IQR) time of the TTE prior to the index surgery was 6 (2-29) days. Operative mortality was 5.8% in the grade III DD group v 2.4% for grade II DD, 1.9% for grade I DD, and 2.1% for no DD (p = 0.001). Atrial fibrillation, prolonged mechanical ventilation (>24 hours), acute kidney injury, any packed red blood cell transfusion, reexploration for bleeding, and length of stay were higher in the grade III DD group compared to the rest of the cohort. The median follow-up was 4.0 (IQR: 1.7-6.5) years. Kaplan-Meier survival estimates were lower in the grade III DD group than in the rest of the cohort.

CONCLUSIONS

These findings suggested that DD may be associated with poor short-term and long-term outcomes.

Association Between Early Extubation and Postoperative Reintubation After Elective Cardiac Surgery: A Bi-institutional Study

OBJECTIVE

It is unknown if remaining intubated after cardiac surgery is associated with a decreased risk of postoperative reintubation. The primary objective of this study was to investigate whether there was an association between the timing of extubation and the risk of reintubation after cardiac surgery.

DESIGN

A retrospective, observational study.

SETTING

Two university-affiliated tertiary care centers.

PARTICIPANTS

A total of 9,517 patients undergoing either isolated coronary artery bypass grafting (CABG) or aortic valve replacement (AVR).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 6,609 isolated CABGs and 2,908 isolated AVRs were performed during the study period. Reintubation occurred in 112 patients (1.64%) after CABG and 44 patients (1.5%) after AVR. After multivariate logistic regression analysis, early extubation (within the first 6 postoperative hours) was not associated with a risk of reintubation after CABG (odds ratio [OR] 0.53, 95% CI 0.26-1.06) and AVR (OR 0.52, 95% CI 0.22-1.22). Risk factors for reintubation included increased age in both the CABG (OR per 10-year increase, 1.63; 95% CI 1.28-2.08) and AVR (OR per 10-year increase, 1.50; 95% CI 1.12-2.01) cohorts. Total bypass time, race, and New York Heart Association (NYHA) functional class were not associated with reintubation risk.

CONCLUSION

Reintubation after CABGs and AVRs is a rare event, and advanced age is an independent risk factor. Risk is not increased with early extubation. This temporal association and low overall rate of reintubation suggest the strategies for extubation should be modified in this patient population.

Impact of Thoracic Radiation on Patients Undergoing Cardiac Surgery

Prior thoracic radiation has been associated with worse outcomes after cardiac surgery. This study sought to report long-term outcomes in patients undergoing surgery for radiation-associated heart disease. This was an observational study of open cardiac surgeries from 2011 and 2018. Patients with a history of malignancy that required thoracic radiation were identified, and this cohort was matched against a non-irradiated comparison group via Mahalanobis distance matching. Kaplan-Meier survival estimation and multivariable Cox regression analysis was performed to assess the long-term impact of thoracic radiation in patients undergoing cardiac surgery. Of the 15,284 patients receiving cardiac surgery in this time-frame, 269 were identified with a history of thoracic radiation for prior malignancy. Patients with prior radiation had increased 1-year and 5-year mortality (P < 0.001), despite no difference for 30-day mortality (P = 0.719), compared to non-irradiated patients. Mahalanobis distance matching yielded 269 equitably matched pairs. On multivariable analysis, patients with prior radiation demonstrated significantly increased hazard of death, as compared to the non-irradiated group (hazard ratio 1.40, 95% confidence interval: 1.02, 1.94, P = 0.038). Patients with radiation for breast cancer demonstrated a non-significant trend toward reduced hazard of death, as compared to patients with more extensive radiation exposure. There was an increase in long-term mortality in patients with prior radiation undergoing cardiac surgery, however open cardiac surgery can safely be performed in these patients with similar operative mortality. These findings may serve as a useful adjunct in shared decision-making for patients and surgeons alike.

The impact of pulmonary artery catheter use in cardiac surgery

OBJECTIVE

Pulmonary artery catheterization provides continuous monitoring of hemodynamic parameters that may aid in the perioperative management of patients undergoing cardiac surgery. However, prior data suggest that pulmonary artery catheterization has limited benefit in intensive care and surgical settings. Thus, this study sought to determine the impact of pulmonary artery catheter insertion on short-term postoperative outcomes in a large, contemporaneous cohort of patients undergoing open cardiac surgery compared with standard central venous pressure monitoring.

METHODS

This was an observational study of open cardiac surgeries from 2010 to 2018. Patients with pulmonary artery catheter insertion were identified and matched against patients without pulmonary artery catheter insertion via 1:1 nearest neighbor propensity matching. Multivariable analysis was performed to assess the impact of pulmonary artery catheterization on operative mortality in the overall cohort, as well as recent heart failure, mitral valve disease, and tricuspid insufficiency subgroups.

RESULTS

Of the 11,820 patients undergoing (Society of Thoracic Surgeons indexed) coronary or valvular surgery, 4605 (39.0%) had pulmonary artery catheter insertion. Propensity score matching yielded 3519 evenly balanced pairs. Compared with central venous pressure monitoring, pulmonary artery catheter use was not associated with improved operative mortality in the overall cohort or in the recent heart failure, mitral valve disease, or tricuspid insufficiency subgroups. Intensive care unit length of stay was longer (P < .001), and there were more packed red blood cell transfusions in the pulmonary artery catheterization group (P < .001); however, postoperative outcomes were otherwise similar, including stroke, sepsis, and new renal failure (P > .05).

CONCLUSIONS

These findings suggest that pulmonary artery catheterization may have limited benefit in cardiac surgery.