Jaimin R. Trivedi

Survival on the Heart Transplant Waiting List: Impact of Continuous Flow Left Ventricular Assist Device as Bridge to Transplant

BACKGROUND Continued donor organ shortage and improved outcomes with current left ventricular assist device (LVAD) technology have increased the number of patients supported with bridge-to-transplantation (BTT) therapy. Using the United Network of Organ Sharing (UNOS) database, we assessed the impact on survival in patients supported with BTT while on the heart transplant waiting list. METHODS The UNOS database was queried from January 2005 to June 2012 to identify patients listed for heart transplantation as UNOS status 1A or 1B. Patients implanted with a pulsatile-flow device or an LVAD other than the HeartMate II (HM II; Thoratec Inc, Pleasanton, CA) were excluded. Patients were divided into LVAD and non-LVAD groups based on status at the time of listing. Patients were propensity matched (LVAD -non-LVAD = 1:2) for age, sex, weight, presence of diabetes, creatinine levels, mean pulmonary artery pressure, and UNOS status. Kaplan-Meier curves were analyzed for survival. RESULTS A total of 8,688 patients were analyzed, with 1,504 (17%) in the LVAD group. Average age (52.6 ± 11.8 versus 51.3 ± 12.9 years; p = 0.0002) and weight (86.6 ± 18.6 versus 80.8 ± 18.2 kg; p < 0.0001) at time of listing were higher in the LVAD group. There were more men (79% versus 74%; p < 0.0001) and more patients with diabetes (30% versus 27%; p = 0.03) in the LVAD group. Of all patients, 6,943 patients (80%) underwent transplantation, 862 (10%) died, and 883 (10%) remained on the waiting list. After propensity matching, survival to transplantation was significantly better in the LVAD group than in the non-LVAD group at both 1 year (91% versus 77%) and 2 years (85% versus 68%). CONCLUSIONS Patients supported with an HM II LVAD as BTT therapy were older with increased comorbidities; they demonstrated an improved survival while listed for heart transplantation. The use of LVADs as a BTT strategy can potentially improve patient survival while waiting for transplantation and allow better allocation of donor hearts.

Heart Transplant vs Left Ventricular Assist Device in Heart Transplant-Eligible Patients

BACKGROUND Patients listed for heart transplant have a prolonged wait time, with continued deterioration, poor quality of life, and 10% mortality. Although recent bridge to transplant (BTT) studies demonstrated 1-year survival similar to heart transplantation, doubt remains about overall effectiveness as a treatment strategy compared with waiting and implanting a left ventricular device (LVAD) only as a last resort. We evaluated 1-year outcome and effectiveness of LVAD vs heart transplantation. METHODS Patients on the heart transplantation list, either receiving an allograft or LVAD for BTT from January 2009 to December 2009 were evaluated. Of 43 patients treated, 1 received both LVAD and an allograft during same admission was removed from the analysis. All patients but one who received an allograft had prior LVAD. Descriptive and univariate (t test) statistics and Kaplan-Meier survival curve were used for analyses. RESULTS LVAD for BTT was used in 29 patients (51.4±12.8 years, 6.9% women), and 13 (51.1±11.6 years, 15.38% women) underwent heart transplantation. Initial hospital length of stay was 17.5±14.4 days in BTT group and 14.3±4.6 days in heart transplant group (p=0.44) At 1 year, the total number of days spent in the hospital (operation and related complications), including index hospitalization was 11.6±14.3 days/100 days in BTT and 7.9±9.0 days/100 days in heart transplantation (p=0.38). A total of 41% BTT and 46% heart transplant patients had one readmission within 3 months of the index hospitalization. Infection was the most common cause of readmission in both groups. The 1-year survival was similar for both groups (no hospital death in either group; 3 late deaths in the BTT group). CONCLUSIONS One-year outcomes for patients eligible for heart transplantation were similar whether they received an allograft or LVAD for BTT. Heart transplant outcome for patients with LVAD were not adversely affected. Improving outcomes for patients treated with LVAD suggest that current decision models for patients eligible for heart transplantation may need to be reevaluated.

Thoracic Aortic Mobile Thrombus: Is There a Role for Early Surgical Intervention?

BACKGROUND The diagnosis of thoracic aortic mobile thrombus (TAMT) is rare and is usually made after debilitating embolic events. The optimal treatment strategy is unknown. We report 14 patients with TAMT and aim to better define the role of early (less than 2 weeks) surgical thrombectomy. METHODS Between February 1996 and February 2010, we treated 14 patients (9 women; aged 32 to 84 years, mean age 51 years) with TAMT. Hypercoagulable disorders or a strong family history of vascular thrombosis, or both, occurred in 9 patients. Diagnosis was made by transesophageal echocardiogram in 6, computed tomography angiography in 7, and digital subtraction angiography in 1. Embolic locations were extremities (n=9), cerebral (n=6), and abdominal (n=6). Aortic thrombi (n=17) locations were ascending/arch (n=7), descending (n=8), and thoracoabdominal (n=2). RESULTS All patients were initially treated with heparin and aspirin. Thoracic aortic thrombectomies were performed in 8 patients within 2 weeks of diagnosis: left thoracotomy (n=5), thoracoabdominal (n=1), and median sternotomy (n=2). Left atrial-femoral bypass was used in 5 patients, cardiopulmonary bypass in 2, and no support in 1. Additional procedures were celiac artery (n=1) and left subclavian artery (n=2) thrombectomies. Procedures for embolic complications were performed in 7 patients before aortic thrombectomy. Operative mortality was 0%, with no recurrent embolic events after 24±16 months. One patient had thrombectomy of the ascending aorta and medical therapy with warfarin and aspirin for a second concurrent small thrombus in the descending aorta. One patient presented with multiorgan failure and died shortly after admission. Six patients treated medically were discharged on a regimen of oral warfarin and aspirin (14±11 months follow-up), with 2 fatal recurrent embolic events within 6 weeks (p=0.09). CONCLUSIONS Thoracic aortic mobile thrombus is rare and is commonly associated with morbid thromboembolic events. In our experience, early surgical aortic thrombectomy had a low operative risk and may prevent fatal recurrent embolic events.

Early and Midterm Outcomes Following Surgery for Acute Type A Aortic Dissection

Surgical repair of acute Type A aortic dissection (AADA) is still associated with high in‐hospital mortality. We evaluated the impact of perioperative risk factors on early and midterm survival.

High sensitivity for lung cancer detection using analysis of exhaled carbonyl compounds.

OBJECTIVE Several volatile carbonyl compounds in exhaled breath have been identified as cancer-specific markers. The potential for these markers to serve as a screening test for lung cancer is reported. METHODS Patients with computed tomography-detected intrathoracic lesions and healthy control participants were enrolled from 2011 onward. One liter of breath was collected from a single exhalation from each participant. The contents were evacuated over a silicon microchip, captured by oximation reaction, and analyzed by mass spectrometry. Concentrations of 2-butanone, 3-hydroxy-2-butanone, 2-hydroxyacetaldehyde, and 4-hydroxyhexanal were measured. The overall population was divided into 3 groups: those with lung cancer, benign disease, and healthy controls. An elevated cancer marker was defined as ≥1.5 SDs above the mean concentration of the control population. One or more elevated cancer markers constituted a positive breath test. RESULTS In all, 156 subjects had lung cancer, 65 had benign disease, and 194 were healthy controls. A total of 103 (66.0%) lung cancer patients were early stage (stage 0, I, and II). For ≥1 elevated cancer marker, breath analysis showed a sensitivity of 93.6%, and a specificity of 85.6% for lung cancer patients. Additionally, 83.7% of stage I tumors ≤2 cm were detected; whereas only 14% of the control population tested positive. In a comparison of cancer to benign disease, specificity was proportional to the number of elevated cancer markers present. CONCLUSIONS Screening using a low-dose CT scan is associated with high cost, repeated radiation exposure, and low accrual. The high sensitivity, convenience, and low cost of breath analysis for carbonyl cancer markers suggests that it has the potential to become a primary screening modality for lung cancer.

Heart Transplant Survival Based on Recipient and Donor Risk Scoring: A UNOS Database Analysis.

Unlike the lung allocation score, currently, there is no quantitative scoring system available for patients on heart transplant waiting list. By using United Network for Organ Sharing (UNOS) data, we aim to generate a scoring system based on the recipient and donor risk factors to predict posttransplant survival. Available UNOS data were queried between 2005 and 2013 for heart transplant recipients aged ≥18 years to create separate cox-proportional hazard models for recipient and donor risk scoring. On the basis of risk scores, recipients were divided into five groups and donors into three groups. Kaplan–Meier curves were used for survival. Total 17,131 patients had heart transplant within specified time period. Major factors within high-risk groups were body mass index > 30 kg/m2 (46%), mean pulmonary artery pressure >30 mmHg (65%), creatinine > 1.5 mg% (63%), bilirubin > 1.5 mg% (54%), noncontinuous-flow left ventricular assist devices (45%) for recipients and gender mismatch (81%) and ischemia time >4 hours (88%) for donors. Survival in recipient groups 1, 2, 3, 4, and 5 at 5 years was 81, 80, 77, 74, and 62%, respectively, and in donor groups 1, 2, and 3 at 5 years was 79, 77, and 70%, respectively (p < 0.001). Combining donor and recipient groups based on scoring showed acceptable survival in low-risk recipients with high-risk donor (75% at 5 years). A higher recipient and donor risk score are associated with worse long-term survival. A low-risk recipient transplanted with high-risk donor has acceptable survival at 5 years, but high-risk recipient combined with a high-risk donor has marginal results. Using an objective scoring system could help get the best results when utilizing high-risk donors.

Double Lung Transplants Have Significantly Improved Survival Compared With Single Lung Transplants in High Lung Allocation Score Patients

BACKGROUND Historically, double lung transplantation survival rates are higher than those of single lung transplantation, but in critically ill patients a single lung transplant, with less associated operative morbidity, could afford a better outcome. This article evaluates how survival is affected in patients who have a high lung allocation score (LAS) and receive a single versus a double lung transplant. METHODS The UNOS Thoracic Transplant Database for lung transplants from January 2005 to June 2012 was used for analysis. Propensity matching was used to minimize differences between the high and low LAS groups and between single and double lung transplants in the high LAS group. RESULTS Within this database, there were 8,778 patients, of whom 8,050 had an LAS less than 75 and 728 had an LAS greater than or equal to 75. Kaplan-Meier survival curves stratified by high and low LAS, and by single versus double lung transplants, showed a marked decrease in survival (p<0.001) in those with a high LAS who received a single lung transplant when compared with those with a high LAS who received a double lung transplant. This was a much greater difference in survival than was present in the low LAS patient population. CONCLUSIONS Despite a higher operative morbidity, patients who had a high LAS did substantially better in terms of survival if two lungs were transplanted rather than only one, with a larger difference in survival than for patients with a lower LAS.

Clinical Outcome After Triple-Valve Operations in the Modern Era: Are Elderly Patients at Increased Surgical Risk?

BACKGROUND Despite modern advances in surgical care, triple-valve surgery (TVS) remains a challenge and carries a mortality of 10% to 20%. No validated risk score is available for TVS, and the effect of advanced age is unknown. This study examined our results in the modern era with the aim of identifying perioperative predictors of adverse outcomes. METHODS Between 1997 and 2013, 131 patients (mean age, 67.2±13.4 years) underwent TVS at our institution. Sixty-eight patients (51.9%) were aged 70 years and older. The most common etiology for aortic and mitral disease was degenerative (77.1%), rheumatic (10%), and endocarditis or prosthetic-related, or both, in the rest. Tricuspid valve disease was functional in 96%. New York Heart Association functional class III/IV was present in 69.4%, and 24% had had previous cardiac operations. One or more concomitant cardiac procedures were performed in 77 patients (58.8%), including coronary revascularization in 54. All aortic procedures were replacements, 14 patients required a prosthetic root conduit and 7 thoracic aorta replacement. Mitral replacements were used in 55%, repairs in 45%, and 96.2% of tricuspid procedures were repairs. Univariate and multivariate analyses were used to determine predictors of adverse outcomes. RESULTS The 30-day and hospital mortality was 10.6% (n=14). Major complications occurred in 70 (53.4%). Univariate analysis identified New York Heart Association functional class III/IV (p=0.04), preoperative renal failure requiring dialysis (p=0.04), urgent operation (p=0.04), intraaortic balloon pump placement (p=0.02), and postoperative low cardiac output (p<0.0001) as predictors for early death. Proximal aortic operations, urgent operation, and New York Heart Association class IV correlated with increased early mortality (p<0.04) in patients aged 70 and older in addition to their decreased overall survival and decreased likelihood of discharge to home. Overall actuarial survival at 1, 5, and 10 years was 84.5%, 75%, and 45%, respectively. CONCLUSIONS TVS remains a surgical challenge in the modern era. Despite a trend of increasing age and surgical risk, the early mortality rate and long-term survival remain respectable. Advanced age is associated with increased perioperative risk, but age per se should not be a contraindication for TVS.

Is Female Sex an Independent Risk Factor for Perioperative Transfusion in Coronary Artery Bypass Graft Surgery

BACKGROUND Perioperative red blood cell transfusion is a risk factor for postoperative mortality and morbidity in coronary artery bypass grafting (CABG). Females have a higher risk of red blood cell transfusion, but few previous studies have accounted for preoperative hematocrit and female sex together as risk factors for red blood cell transfusion. We evaluated female sex as an independent risk factor for red blood cell transfusion in CABG, while accounting for hematocrit. STUDY DESIGN A cardiac surgery database was reviewed for isolated, primary, first-time CABG operations from a single center from January 2005 to June 2009. Demographic and clinical variables were evaluated as risk factors of red blood cell transfusion using univariate (Student t-test and chi-square test) and multivariate (logistic regression) analyses. RESULTS Of 2,107 patients (ALL-patients) reviewed, 640 had known hematocrit (KNOWN-Hct). Women had lower hematocrit (35.77% ± 4.07% vs 40.06% ± 4.79% for men). On multivariate analysis of ALL-patients, older age, smaller body surface area, and female sex were risk factors; higher ejection fraction and off-pump surgery were associated with less red blood cell transfusion. On multivariate analysis of KNOWN-Hct, older age, lower hematocrit, smaller body surface area, and lower ejection fraction were risk factors of red blood cell transfusion and sex was not a significant risk factor in this group. CONCLUSIONS Female sex is not an independent risk factor for red blood cell transfusion in CABG when preoperative hematocrit is included as a covariate in a multivariable model. A lower hematocrit could explain some of the sex-specific disparities in outcomes after CABG and should be included in future analyses.

Proximal Thoracic Aortic Replacement for Aneurysmal Disease Using the Freestyle Stentless Bioprosthesis: A 10-Year Experience

BACKGROUND Porcine bioprosthesis (bioroots) are an attractive surgical strategy for ascending aorta and arch replacement. This study evaluated the perioperative and late outcomes using this strategy for proximal aortic aneurysmal disease. METHODS Between March 1998 and November 2009, 170 patients (40% women; median age, 70 years) underwent proximal thoracic aortic replacement using the Freestyle (Medtronics Inc, Minneapolis, MN) bioroot, with graft extension in 149 (87.6%). Aneurysmal etiology included degenerative-atherosclerotic (91.2%), acute dissection (5.3%), and chronic dissection (3.5%); 78% had greater than moderate aortic insufficiency. Surgical procedures were bioroot alone or with aortoplasty (12.3%), bioroot with ascending aortic graft (38.2%), bioroot with hemiarch graft (44.1%), and bioroot with total arch (5.3%). Hypothermic circulatory arrest was required in 49%. RESULTS The 30-day mortality was 4.7% (n=8). The overall complication rate was 58% (n=100), including stroke (6.5%), renal failure (9.2%), respiratory failure (25.9%), and postoperative bleeding (7.6%). Mean hospitalization was 10.5±7.3 days; 38 were discharged to a rehabilitation facility (23.5%). Predictors of 30-day/hospital death were coronary artery disease (p=0.0003), renal insufficiency (p<0.0001), emergent/urgent procedure (p=0.02), and hypothermic circulatory arrest (p=0.002). The 1-year, 5-year, and 10-year survivals were 90%, 80%, and 35% respectively. Freedom from endocarditis and reoperation was 96% at 1 year and 94% and 95% at 5 years, respectively. CONCLUSIONS Proximal thoracic aortic replacement using a porcine bioroot as part of the repair can be achieved with low perioperative mortality and acceptable late survival in a predominantly elderly population.