Pulmonary-Systemic Pressure Ratio Correlates with Morbidity in Cardiac Valve Surgery.

OBJECTIVES: Pulmonary hypertension portends worse outcomes in cardiac valve surgery; however, isolated pulmonary artery pressures may not reflect patients' global cardiac function accurately. To better account for the interventricular relationship, the authors hypothesized that patients with greater pulmonary-systemic ratios (mean pulmonary arterial pressure)/(mean systemic arterial pressure) would correlate with worse outcomes after valve surgery. DESIGN: Retrospective cohort study. SETTING: Single academic hospital. PARTICIPANTS: The study comprised 314 patients undergoing valve surgery with or without coronary artery bypass grafting (2004-2016) with Society of Thoracic Surgeons predicted risk scores and preoperative right heart catheterization. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The pulmonary-systemic ratio was calculated as follows: mean pulmonary arterial pressure/mean systemic arterial pressure. Patients were stratified by pulmonary-systemic ratio quartile. Logistic regression was used to assess the risk-adjusted association between pulmonary-systemic ratio or mean pulmonary arterial pressure. Median pulmonary-systemic ratio was 0.33 (Q1-Q3: 0.23-0.65); median pulmonary arterial pressure was 29 (21-30) mmHg. Patients with the highest pulmonary-systemic ratio had the highest rates of morbidity and mortality (p < 0.0001). A high pulmonary-systemic ratio was associated with longer duration in the intensive care unit (p < 0.0001) and hospital (p < 0.0001). After risk-adjustment, pulmonary-systemic ratio and pulmonary arterial pressure were independently associated with morbidity and mortality, but the pulmonary-systemic ratio (odds ratio 23.88, p = 0.008, Wald 7.1) was more strongly associated than the pulmonary arterial pressure (odds ratio 1.035, p = 0.011, Wald 6.5). CONCLUSIONS: The pulmonary-systemic ratio is more strongly associated with risk-adjusted morbidity and mortality in valve surgery than pulmonary arterial pressure. By integrating ventricular interactions, this metric may better characterize the risk of valve surgery.

Preoperative ß-blocker use correlates with worse outcomes in patients undergoing aortic valve replacement.

OBJECTIVES: ß-Blocker use is associated with fewer cardiac complications in patients undergoing noncardiac surgery and is a quality metric for coronary artery bypass grafting. We sought to determine the influence of preoperative ß-blocker administration before aortic valve replacement (AVR). METHODS: All patients undergoing isolated AVR from 2002 to 2016 were extracted from a multi-institutional, statewide database composed of Society of Thoracic Surgeons data. Patients were propensity score matched by preoperative and operative variables, and the effects of preoperative ß-blockers on outcomes were assessed. RESULTS: Of 7380 eligible patients, 53% received a preoperative ß-blocker. After propensity matching, a total of 4592 patients were well matched (1:1) with minimal baseline differences between groups. Within the matched cohort, the operative mortality rate (ß-blocker: 2.8% vs no ß-blocker: 2.4%; P = .454) and rate of major morbidity (14.4% vs 12.7%; P = .101) were similar between groups. The rates of cardiac arrest (2.1% vs 1.3%; P = .034), renal failure requiring dialysis (1.7% vs 0.9%; P = .007), and postoperative transfusion (38.2% vs 33.8%; P = .002) after AVR were significantly greater in the cohort receiving preoperative ß-blockade. Postoperative atrial fibrillation was also more prevalent in patients receiving a preoperative ß-blocker (26.9% vs 23.4%; P = .007). Finally, preoperative ß-blocker use was associated with longer postoperative intensive care unit stays (45.2 vs 47.0 hours; P = .001), but clinically similar hospital length of stay. CONCLUSIONS: Preoperative ß-blocker administration is not associated with improved outcomes after AVR but instead is associated with increased postoperative morbidity. Routinely initiating preoperative ß-blockade is not supported in patients undergoing AVR.

Transcatheter interventions for functional mitral regurgitation.

Mitral regurgitation is considered the most prevalent valve disease in the United States and its incidence is increasing due to the aging population. Surgical mitral valve repair and replacement are effective at reducing regurgitation due to ischemia, but many patients with secondary mitral regurgitation do not undergo surgery because they are too high risk. Transcatheter devices that mimic surgical techniques are rapidly being developed to reduce the risks traditionally associated with surgical mitral valve repair and replacement. Despite the challenges posed by complex anatomy and multiple etiologies of mitral valve pathology, early results of transcatheter mitral repair and replacement indicate that they have the potential to increase the number of patients with secondary MR who are candidates for intervention.

Cardiothoracic surgery training grants provide protected research time vital to the development of academic surgeons.

BACKGROUND: The Ruth L. Kirschstein Institutional National Research Service Award (T32) provides institutions with financial support to prepare trainees for careers in academic medicine. In 1990, the Cardiac Surgery Branch of the National Heart, Lung and Blood Institute (NHLBI) was replaced by T32 training grants, which became crucial sources of funding for cardiothoracic (CT) surgical research. We hypothesized that T32 grants would be valuable for CT surgery training and yield significant publications and subsequent funding. METHODS: Data on all trainees (past and present) supported by CT T32 grants at two institutions were obtained (T32), along with information on trainees from two similarly sized programs without CT T32 funding (Non-T32). Data collected were publicly available and included publications, funding, degrees, fellowships, and academic rank. Non-surgery residents and residents who did not pursue CT surgery were excluded. RESULTS: Out of 76 T32 trainees and 294 Non-T32 trainees, data on 62 current trainees or current CT surgeons (T32: 42 vs Control: 20) were included. Trainees who were supported by a CT T32 grant were more likely to pursue CT surgery after residency (T32: 40% [30/76] vs Non-T32: 7% [20/294], P < .0001), publish manuscripts during residency years (P < .0001), obtain subsequent NIH funding (T32: 33% [7/21] vs Non-T32: 5% [1/20], P = .02), and pursue advanced fellowships (T32: 41% [9/22] vs Non-T32: 10% [2/20], P = .02). CONCLUSIONS: T32 training grants supporting CT surgery research are vital to develop academic surgeons. These results support continued funding by the NHLBI to effectively develop and train the next generation of academic CT surgeons.

Mitral Valve Repair: The French Correction Versus the American Correction.

Degenerative mitral valve disease causing mitral regurgitation is the most common organic valve pathology and is classified based on leaflet motion. The "French correction" mitral valve repair method restores normal valvular anatomy with extensive leaflet resection, chordal manipulation, and rigid annuloplasty. The American correction attempts to restore normal valve function through minimal leaflet resection, flexible annuloplasty, and use of artificial chordae. These differing methods of mitral valve repair reflect an evolution in principles, but both require understanding of the valve pathology and correction of leaflet prolapse and annular dilatation. Adhering to those unifying principles and ensuring that no patient leaves the operating room with significant persistent mitral regurgitation produces durable results and satisfactory patient outcomes.

A New Intraoperative Protocol for Reducing Perioperative Transfusions in Cardiac Surgery.

BACKGROUND: Perioperative anemia and blood product transfusion increases short-term and long-term morbidity and mortality during cardiac surgery. We hypothesized that streamlined cardiopulmonary bypass circuit and rotational thromboelastometry (ROTEM) would reduce blood product usage and improve outcomes. METHODS: All patients with Society of Thoracic Surgeons risk scores at our institution from January 2013 to June 2015 were included. Individuals were chronologically stratified into 2 groups according to institutional changes to a streamlined bypass circuit and ROTEM-guided transfusion. Blood product transfusion, hematocrit, and observed to expected outcomes (O/E) were compared between the groups. RESULTS: Patients were defined as either control group (533 patients, 12 months) or intervention group (804 patients, 18 months). The intervention group was further subdivided into streamlined circuit (290 patients, 6 months) and ROTEM (514 patients, 12 months). Use of streamlined bypass circuit correlated with significantly reduced intraoperative transfusion of packed red blood cells (pRBCs) (23.8% versus 17.9%; p = 0.05) and platelets (28.0% versus 19.3; p = 0.01) with improvement in lowest intraoperative hematocrit (26.0 versus 26.9; p = 0.02). ROTEM was associated with a further reduction in intraoperative pRBCs (17.9% versus 11.28%; p = 0.01) and postoperative transfusion pRBCs (38.3% versus 23.5%; p = 0.02). The combination was associated with reduced intraoperative (44.6% versus 34.1; p < 0.001) and postoperative transfusions (45.6% versus 40.1; p < 0.001) in the intervention group, while maintaining a higher hematocrit at discharge (28.1 versus 29.1; p < 0.001). Finally, the intervention was associated with a statistically significant reduction in the O/E for reoperation (p = 0.003). CONCLUSIONS: Use of streamlined cardiopulmonary bypass circuit and ROTEM may reduce transfusion and reoperation rates and improve perioperative anemia in cardiac surgical patients. This study demonstrates reproducible intraoperative methods for reducing blood product usage and improving outcomes.

Natural history of coexistent mitral regurgitation after aortic valve replacement.

OBJECTIVES: The long-term evolution of coexistent mitral regurgitation (MR) after aortic valve replacement (AVR) for aortic stenosis remains poorly defined. Prior studies have demonstrated that acute improvement in MR after AVR is modest, and more aggressive approaches have been advocated. This study examines the evolution of MR after AVR and identifies prognostic indicators for MR improvement. METHODS: We retrospectively evaluated demographic and echocardiographic data of 423 patients who underwent primary isolated AVR for aortic stenosis with coexistent mild (n = 314) or moderate (n = 109) MR at our institution, from 2004 to 2013. For each patient, preoperative and postoperative MR was extracted from 903 echocardiograms and graded on a 0 to 4+ scale. Hierarchic linear models were used to estimate postoperative residual MR over a 5-year follow-up period. Patients were then stratified by improvement in MR, and preoperative risk factors and survival were compared between groups. Cox proportional hazards regression was used to assess the association between survival and preoperative and postoperative MR. RESULTS: The overall acute reduction in MR was -0.23 degrees per patient. Patients with moderate MR had a -0.53 degree reduction in MR, whereas patients with mild MR had only a -0.13 degree reduction in MR (P < .001). Residual MR, however, worsened over time and regressed back to baseline, particularly in patients with preoperative moderate MR. At last follow-up, 70 (17%) patients returned to 2+ or worse MR. Residual MR at last echocardiographic follow-up was not affected by left ventricular ejection fraction, severity of preoperative aortic valve gradient (AVG), magnitude of reduction of AVG, or other comorbidities. Degree of preoperative MR did not affect midterm survival. Patients whose MR improved after AVR demonstrated a trend toward improved survival (75% vs 65% 5-year survival; P = .06), compared with those without MR whose survival remained unchanged or worsened. CONCLUSIONS: Coexistent MR modestly improves after AVR, but eventually regresses back to baseline or worsens over time in many patients. Preoperative AVG, reduction of AVG, heart failure, or atrial fibrillation was not predictive of residual MR. Moderate preoperative MR did not adversely affect 5-year survival. Patients with improvement in MR, however, demonstrated a trend toward improved survival at 5 years. More aggressive approaches for coexistent moderate MR should be considered in patients who need AVR for aortic stenosis.

Early outcomes of pulmonary valve replacement with the mitroflow bovine pericardial bioprosthesis.

BACKGROUND: Bovine pericardial valves are often used for pulmonary valve replacement (PVR) in patients with previously repaired congenital heart disease. Attention has recently focused on the safety of the Mitroflow (Sorin Group USA, Arvada, CO) bovine pericardial valve after a national alert describing several cases of sudden valve failure in young patients. In response, we reviewed our experience using the Mitroflow bioprosthesis for PVR. METHODS: Medical records were reviewed for all patients who underwent PVR using a Mitroflow valve at our center (2008-2013). RESULTS: The cohort included 84 patients with a median age of 18.3 years (range, 0.8-62.1 years) and weight of 48.4 kg (range, 5.7-167.8 kg). Indications for surgical intervention included native outflow tract insufficiency (59 patients), valved conduit failure (20 patients), and isolated prosthetic valve failure (5 patients). Median length of stay was 3 days (range, 2-13 days). There were no hospital deaths. Median follow-up was 2.4 years (range, 0.2-5.6 years). Pulmonary valve insufficiency and peak gradient increased with time. At latest follow-up, freedom from insufficiency greater than or equal to a moderate degree was 83%, and freedom from a peak gradient greater than or equal to 50 mm Hg was 92%. Reintervention was required in 4 patients. One patient experienced endocarditis and underwent surgical PVR (0.6 years after initial intervention). Three patients underwent transcatheter treatment for valve stenosis including PVR (at 4.2 and 4.4 years in 2 patients) and balloon valvuloplasty (at 5.2 years in the third patient). Kaplan-Meier freedom from reintervention at 5 years was 81%. CONCLUSIONS: Early outcomes using the Mitroflow bovine pericardial valve for PVR in children and adults with repaired congenital heart disease appear acceptable and similar to reported outcomes for other tissue valve options. Valve failure from premature structural deterioration was not observed.

Hemolysis and Pulmonary Insufficiency following Right Ventricular Assist Device Implantation.

We report a case of severe hemolysis and pulmonary valve insufficiency (PI) following right ventricular support using a paracorporeal pneumatic pump (Abiomed, Danvers, MA, USA). We speculate that the high velocity jet of blood emanating from the outflow cannula caused turbulence above the pulmonary valve, leading to PI and hemolysis. Despite the growing number of implanted ventricular assist devices, we could find no report in the literature describing pulmonary valve insufficiency secondary to right ventricular assist device (RVAD) placement. Fortunately, in this case, right ventricular function recovered sufficiently after seven days of support, allowing explantation of the device and resolution of PI and hemolysis.