Proof of Concept: Development of a Mitral Annuloplasty Ring With Crosshatch Net.

OBJECTIVE: Here we report our preclinical, proof-of-concept testing to assess the ability of a novel device to correct mitral regurgitation. The Milwaukee Heart device aims to enable any cardiac surgeon to perform high-quality mitral valve repair using a standard annuloplasty ring with a crosshatch of microporous, monofilament suture. METHODS: Hemodynamic, echocardiographic, and videographic data were collected at baseline, following induction of mitral regurgitation, and after repair using porcine hearts in an ex vivo biosimulator model. A commercially available cardiac prosthesis assessment platform was then used to assess the hydrodynamic characteristics of the study device. RESULTS: Porcine biosimulator pressure and flow metrics exhibited successful correction of mitral regurgitation following device implantation with similar values to baseline. Hydrodynamic results yielded pressure gradients and an effective orifice area comparable to currently approved prostheses. CONCLUSIONS: The study device effectively reduced mitral valve regurgitation and improved hemodynamics in our preclinical model with similar biophysical metrics to currently approved devices. Future in vivo trials are needed to evaluate the efficacy, biocompatibility, and freedom from the most likely adverse events, such as device thrombosis, embolic events, and hemolysis.

Supporting the right ventricle in postcardiotomy renal dysfunction: A case series.

Postcardiotomy RV dysfunction is an under-recognized cause of acute kidney injury (AKI). Insertion of a percutaneous right ventricular assist device (RVAD) reduces central venous hypertension and congestive nephropathy by augmenting cardiac output. In selected patients, percutaneous RVAD insertion may improve renal function and obviate the need for long-term dialysis.

Transplantation Outcomes with Donor Hearts after Circulatory Death.

BACKGROUND: Data showing the efficacy and safety of the transplantation of hearts obtained from donors after circulatory death as compared with hearts obtained from donors after brain death are limited. METHODS: We conducted a randomized, noninferiority trial in which adult candidates for heart transplantation were assigned in a 3:1 ratio to receive a heart after the circulatory death of the donor or a heart from a donor after brain death if that heart was available first (circulatory-death group) or to receive only a heart that had been preserved with the use of traditional cold storage after the brain death of the donor (brain-death group). The primary end point was the risk-adjusted survival at 6 months in the as-treated circulatory-death group as compared with the brain-death group. The primary safety end point was serious adverse events associated with the heart graft at 30 days after transplantation. RESULTS: A total of 180 patients underwent transplantation; 90 (assigned to the circulatory-death group) received a heart donated after circulatory death and 90 (regardless of group assignment) received a heart donated after brain death. A total of 166 transplant recipients were included in the as-treated primary analysis (80 who received a heart from a circulatory-death donor and 86 who received a heart from a brain-death donor). The risk-adjusted 6-month survival in the as-treated population was 94% (95% confidence interval [CI], 88 to 99) among recipients of a heart from a circulatory-death donor, as compared with 90% (95% CI, 84 to 97) among recipients of a heart from a brain-death donor (least-squares mean difference, -3 percentage points; 90% CI, -10 to 3; P<0.001 for noninferiority [margin, 20 percentage points]). There were no substantial between-group differences in the mean per-patient number of serious adverse events associated with the heart graft at 30 days after transplantation. CONCLUSIONS: In this trial, risk-adjusted survival at 6 months after transplantation with a donor heart that had been reanimated and assessed with the use of extracorporeal nonischemic perfusion after circulatory death was not inferior to that after standard-care transplantation with a donor heart that had been preserved with the use of cold storage after brain death. (Funded by TransMedics; ClinicalTrials.gov number, NCT03831048.).

Building cardiac surgical programs in lower-middle income countries.

Objectives: Medical care in low-income countries is often limited by inadequate resources, treatment facilities, and the necessary infrastructure for healthcare delivery. We hypothesized that the development of an independently functioning, internationally supported Kenyan cardiac surgical training program could address these issues through targeted investment. Methods: A review was conducted of the programmatic structure and clinical outcomes from January 2008 to October 2021 at Tenwek Hospital, Bomet, Kenya. Program development phases included (1) cardiovascular care provided by 1 full-time US board-certified cardiothoracic surgeon; (2) short-term volunteer surgical teams from the United States and Canada; and (3) development of a cardiothoracic residency program based on the Society of Thoracic Surgeons training curriculum. Patient demographics and outcomes were analyzed throughout each phase of program development. Results: A total of 817 cardiac procedures were performed during the study period, including 236 congenital (28.8%) and 581 adult (71.1%) procedures. Endemic rheumatic valvular heart disease predominated (581 patients, 62.3%). Local surgical team case volume grew over the study period, overtaking visiting team volume in 2019. Perioperative mortality was 2.1% and consistent between the visiting teams and the locally trained teams. Surgical training via a 3-year cardiothoracic residency is now in its fourth year, with the 2 graduates now retained as full-time teaching staff. Conclusions: Global health partnerships have the potential to address unmet needs in cardiac care within low- and middle-income countries. These data support the concept that acceptable clinical outcomes and consistent growth in volume can be achieved during the transition toward fully independent cardiac surgical care.

Reduced Morbidity and Mortality Associated With Minimally Invasive Single-vessel Coronary Artery Bypass Compared With Conventional Sternotomy.

OBJECTIVE: We aimed to describe the safety and clinical benefits of minimally invasive, nonsternotomy coronary artery bypass grafting (MICABG) using data from The Society of Thoracic Surgeons (STS) National Database. BACKGROUND: MICABG has gained popularity, owing to expected lower perioperative morbidity and shorter recovery. Despite this, concerns remain regarding anastomotic quality and the validity of proposed perioperative benefits. METHODS: We queried the STS National Database for all patients who underwent single-vessel coronary artery bypass grafting (CABG) from January 2014 to December 2016 to compare outcomes of MICABG with conventional CABG. Patients who underwent concomitant or emergent procedures were excluded. Propensity-weighted cohorts were compared by operative approach with adjustment for variability across institutions. RESULTS: Of 12,406 eligible patients, 2688 (21.7%) underwent MICABG, and 9818 (78.3%) underwent conventional CABG. Propensity weighting produced excellent balance in patient characteristics, including completeness of revascularization, body mass index, and STS predictive risk scores. MICABG was associated with significant reduction of in-hospital mortality [odds ratio (OR)=0.32, absolute reduction (AR)=0.91%, P <0.0001]; 30-day mortality (OR=0.51, AR=0.88%, P =0.001), duration of ventilation (8.62 vs 12.6 hours, P <0.0001), prolonged hospitalization (OR=0.77, AR=1.6, P =0.043), deep wound infection (OR=0.33, AR=0.68, P <0.004), postoperative transfusions (OR=0.52, AR=7.7%, P <0.0001), and STS composite morbidity (OR=0.72, AR=1.19%, P =0.008). Subgroup analysis of only off-pump left internal mammary artery-left anterior descending CABG showed similar findings. Major adverse cardiac events and graft occlusion did not differ between groups. CONCLUSIONS: MICABG is associated with lower mortality and perioperative morbidity compared with conventional sternotomy CABG. MICABG may have a role in treating single-vessel disease.

Peripherally inserted concomitant surgical right and left ventricular support, the Propella, is associated with low rates of limb ischemia, with mortality comparable with peripheral venoarterial extracorporeal membrane oxygenation.

BACKGROUND: Mechanical circulatory support effectively treats adult cardiogenic shock. Whereas cardiogenic shock confers high mortality, acute limb ischemia is a known complication of mechanical circulatory support that confers significant morbidity. We compared our novel approach to peripheral mechanical circulatory support with a conventional femoral approach, with a focus on the incidence of acute limb ischemia. METHODS: This was a retrospective cohort study of patients treated with mechanical circulatory support between January 1, 2015 and December 5, 2021 at our institution. Patients receiving any femoral peripheral venoarterial extracorporeal membrane oxygenation were compared with those receiving minimally invasive, peripherally inserted, concomitant right and left ventricular assist devices. These included the Impella 5.0 (Abiomed, Danvers, MA) left ventricular assist device and the ProtekDuo (LivaNova, London, UK) right ventricular assist device used concomitantly (Propella) approach. The primary outcome was incidence of acute limb ischemia. The baseline patient characteristics, hemodynamic data, and post-mechanical circulatory support outcomes were collected. Fisher exact test and Wilcoxon rank sum test was used for the categorical and continuous variables, respectively. Kaplan-Meier curves and log-rank test were used to estimate overall survival probabilities and survival experience, respectively. RESULTS: Fifty patients were treated with mechanical circulatory support at our institution for cardiogenic shock, with 13 patients supported with the novel Propella strategy and 37 with peripheral venoarterial extracorporeal membrane oxygenation. The baseline characteristics, including patient organ function and medical comorbidities, were similar among the groups. Nine patients suffered mortality in ≤48 hours of mechanical circulatory support initiation and were excluded. Twenty patients (69%) suffered acute limb ischemia in the peripheral venoarterial extracorporeal membrane oxygenation group; 0 patients receiving Propella suffered acute limb ischemia (P < .001). The percentages of patients surviving to discharge in peripheral venoarterial extracorporeal membrane oxygenation and Propella groups were 24% and 69%, respectively (P = .007). CONCLUSION: Patients treated with the Propella experienced a lower incidence of acute limb ischemia compared with patients treated with peripheral venoarterial extracorporeal membrane oxygenation.

The effect of socioeconomic factors on patient outcomes in cardiac surgery.

OBJECTIVES: Healthcare delivery is heterogenous; the reasons for this are numerous and complex. Patient-specific factors including geography, income, insurance status, age, and gender have been shown to bias surgical outcomes. Utilizing a prospectively collected all-payer database, we aim to evaluate the influence of socioeconomic factors on mortality and length of stay (LOS) after common cardiac surgical procedures. METHODS: We utilized the National Inpatient Sample, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality for the year 2019. We included patients undergoing coronary artery bypass grafting (CABG), aortic valve replacement (AVR), transcatheter aortic valve replacement (TAVR), and combined AVR/CABG using the 10th revision of the International Classification of Diseases procedure codes. AVR and CABG were combined into a separate cohort as this was felt to represent a different pathology than isolated valvular or coronary arterial disease. Baseline demographics were summarized. Multivariable regression was performed within each procedure group to model the odds of in-hospital mortality and hospital LOS with age, sex, insurance, zip-code median household income, and location as predictors. RESULTS: Baseline patient characteristics including gender, income, geography, and payer status were similar between CABG, AVR, and AVR/CABG. TAVR patients had a higher proportion of female sex and Medicare as the primary payer, with an overall greater age. Multivariable Cox proportional hazards regression found that higher income was strongly associated with decreased LOS following AVR and CABG, and moderately associated in TAVR and AVR/CABG. Private insurance was associated with a decreased LOS in patients undergoing CABG, AVR, TAVR, and AVR/CABG. Female sex and increased age were associated with increased odds of mortality in TAVR, CABG, and AVR/CABG. Private insurance was associated with a decreased odds of mortality in patients undergoing AVR. CONCLUSIONS: These findings reveal significant disparities in patient outcomes after routine cardiac operations that are associated with socioeconomic status. Patients who did not have private insurance or had lower incomes were found to be at risk for increased LOS. Women were at a higher risk of mortality for several operations, a finding which has been previously described elsewhere. Private insurance conveyed a decreased odds of mortality in patients undergoing AVR. This data set serves to highlight differences in healthcare outcomes based on a variety of socioeconomic, geographic, and other inherent factors. Additional research is needed to identify the mechanisms behind these disparities with the goal of providing equitable care to all patients.

Predictive Model for Heart Failure Readmission Using Nationwide Readmissions Database.

Objective: To generate a heart failure (HF) readmission prediction model using the Nationwide Readmissions Database to guide management and reduce HF readmissions. Patients and Methods: A retrospective analysis was performed for patients listed for HF admissions in the Nationwide Readmissions Database from January 1, 2010, to December 31, 2014. A Cox proportional hazards model for sample survey data for the prediction of readmission for all patients with HF was implemented using a derivation cohort (2010-2012). We generated receiver operating characteristic (ROC) curves and estimated area under the ROC curve at each time point (30, 60, 90, and 180 days) to assess the accuracy of our predictive model using the derivation cohort (2010-2012) and compared it with the validation cohort (2013-2014). A risk score was computed for the validation cohort. On the basis of the total risk score, we calculated the probability of readmission at 30, 60, 90, and 180 days. Results: Approximately 1,420,564 patients were admitted for HF, contributing to 1,817,735 total HF admissions. Of these, 665,867 patients had at least 1 readmission for HF. The 10 most common comorbidities for readmitted patients included hypertension, diabetes mellitus, renal failure, chronic pulmonary disease, deficiency anemia, fluid and electrolyte disorders, obesity, hypothyroidism, peripheral vascular disorders, and depression. The area under the ROC curve for the prediction model was 0.58 in the derivation cohort and 0.59 in the validation cohort. Conclusion: The prediction model will find clinical utility at point of care in optimizing the management of patients with HF and reducing HF readmissions.

Thoracoabdominal Normothermic Regional Perfusion for Cardiac Procurement.

In donation after circulatory death donors, warm ischemia time is a significant threat to successful cardiac transplantation. The ability to perfuse these organs during the minutes after death, until cardiac evaluation is completed to satisfaction, is crucial in limiting total warm ischemic time. Thoracoabdominal normothermic regional perfusion (TANRP) has emerged as a promising strategy for recovering and monitoring these hearts. We propose a series of clinical practice pearls that we follow for all donation after circulatory death procurements to streamline the process of setting up a TANRP circuit and ensuring all team members present at time procurement are familiar with the procedure. Bicaval cannulation is achieved via the abdomen for aortic cannulation, and via the chest for right atrial cannulation, avoiding deairing maneuvers and providing the shortest possible duration from incision to initiation of cardiopulmonary bypass. Here, we describe a series of practice techniques which we have utilized in our early experience with TANRP.

Isolated left ventricular assist device implantation produces variable changes to patient body mass index.

BACKGROUND: Body mass index (BMI) is an important consideration for transplant-eligible left ventricular assist device (LVAD) recipients. LVAD therapy's impact on BMI is unclear. We evaluated BMI changes in patients who underwent LVAD implantation. The association between these patients' BMI and the transplant was studied. METHODS: This was a retrospective cohort study of patients who underwent LVAD implantation between January 1, 2012 and December 31, 2018 at our institution. Patients were stratified by preoperative BMI (kg/m2 ) into four groups: <30, 30-34.9, 34.9-39.9, and ≥40. BMI data were collected at 12 and 6 months prior to implantation, time of implantation, and 3- and 6- months postimplantation. RESULTS: A total of 107 patients underwent LVAD implantation at our institution. Data were available for 80 patients. Baseline characteristics included a mean age of 56.0 years, 69% male, and a mean implant BMI of 29.9 ± 6.8 kg/m2 . The mean BMI (kg/m2 ) for each of the BMI (kg/m2 ) groups <30, 30-34.9, 35-39.9, and ≥40 (n = 60, 25, 12, and 10, respectively) was 25.1, 32.5, 36.8, and 43.8, respectively. There was no consistent pattern with weight change across differing implant BMIs. No patient with a BMI of <30 gained sufficient weight to impact transplant candidacy. Twenty-three percent of patients with a BMI of 30-34.9 kg/m2 , 60% of patients with a BMI of 35-39.9 kg/m2 , and 87.5% of patients with a BMI of ≥40 kg/m2 had a 6-month BMI potentially affecting transplant. CONCLUSIONS: Associated weight changes during LVAD support may significantly impact transplant candidacy. Higher BMI groups may benefit from multimodal and multidisciplinary targeted weight-loss interventions.

Protocolized screening effectively identifies myocardial recovery following destination therapy left ventricular assist device implantation.

BACKGROUND: Myocardial recovery following left ventricular assist device (LVAD) implantation has been of interest in transplant candidates with non-ischemic cardiomyopathy but is rare. Evidence suggests that a combination of left ventricular unloading and pharmacologic reverse remodeling is beneficial. Recovery in non-transplant candidates (i.e., destination therapy [DT]) patients is believed to be even rarer. METHODS: All DT LVADs between January 1, 2017 and November 23, 2020 were reviewed. All patients were subjected to an institutional protocol consisting of combined pharmacologic remodeling and mechanical unloading with proactive screening for recovery. The primary outcome of interest was the cumulative incidence of myocardial recovery. Baseline characteristics and operative outcomes were compared between recovered and non-recovered DT patients using non-parametric tests to identify predictive factors. RESULTS: A total of 49 patients received DT LVADs. Nine patients were identified as myocardial recovery candidates using the protocol screening criteria. Overall, 11 patients underwent formal confirmatory testing for recovery, of which 10 were deemed recovered and underwent LVAD explant, defunctionalization, or transplantation. 37.5% of patients that had a concomitant coronary artery bypass during LVAD implantation achieved recovery. An equal proportion of ischemic and non-ischemic cardiomyopathy patients achieved recovery. The cumulative incidence of myocardial recovery was 25.1% at 36 months. No factors were identified as being predictive of recovery. CONCLUSION: Myocardial recovery in DT LVAD patients can be achieved at a higher rate than previously reported. Revascularization at the time of LVAD is safe and may be beneficial. LVAD therapy may not be the final destination in these patients.

Catheter-based system for the treatment of left ventricular assist device thrombosis.

BACKGROUND: Thrombotic complications continue to pose challenges to patients on left ventricular assist device (LVAD) support. The Hoplon system was developed to administer catheter-based lytic therapy with a novel approach to embolic protection. METHODS: Two porcine non-survival surgeries were performed in which off-pump LVAD insertion was followed by injection of thrombus into the impeller, isolation of the pump using the Hoplon system, and administration of lytic therapy to the pump chamber. Successful thrombus resolution was confirmed by pathological examination of the LVAD and brain tissue after animal sacrifice. RESULTS: Limitations of the prototype design resulted in the extrusion of thrombus from around the catheter in the first animal. Subsequent device modifications resulted in the resolution of LVAD thrombus as confirmed on removal and examination of the pump. Pathological examination of the brain tissue revealed the absence of any embolic or hemorrhagic complications. CONCLUSIONS: Early animal studies suggest feasibility in restoring function to an LVAD while at the same time preventing cerebroembolic events using the Hoplon system.

Transcarotid Approach to Placement of an Impella 5.0.

Microaxial left ventricular assist devices (mLVADs) have traditionally been placed through a transfemoral or transaxillary arterial approach. Transfemoral access is restrictive, significantly limiting postoperative patient ambulation. Transaxillary placement is preferred but not feasible in a subset of patients due to small arterial diameter or tight angulation of the thoracic outlet. Transcarotid delivery has been utilized for other cardiovascular device deployment with good success; however, this approach has not been described for mLVAD support. We present a case series of transcarotid placement of mLVADs in cases where a transaxillary and transfemoral approach was not feasible. From May 2017 to April 2019, six patients in cardiogenic shock required mLVAD support achieved via a transcarotid approach. Technical success was achieved in all patients. One patient was directly weaned from mLVAD support and two patients died on mLVAD support. Escalation to venoarterial extracorporeal membrane oxygenation (VA-ECMO) was required for three patients, two of whom subsequently died. There were no bleeding or valvular complications related to device placement, and no obvious or known neurologic complications related to mLVAD support. Transcarotid placement of mLVADs expands the utility of these devices as an alternative to traditional support strategies or prohibitive arterial anatomy; however, further study is needed to determine its efficacy.

How Does Multiple Listing Affect Lung Transplantation? A Retrospective Analysis.

The impact of multiple listing (ML) strategies on lung transplantation is unknown. Retrospective review of United Network for Organ Sharing (UNOS) registry for lung transplantation between May 1, 2005 and March 31, 2017 was performed. Characteristics of single (SL) and ML candidates were compared, and incidence density matching was used to select up to 10 controls for each case. Overall survival was evaluated using Cox regression stratified by matched sets. Nelson-Aalen estimators were used to estimate the cumulative incidence (CI) of transplant, death on the waiting list, and removal from wait-list as competing risks; Gray's test was used to compare wait list outcomes between groups. 23,445 subjects listed for lung transplant, of which 467 (2%) subjects listed at 2+ centers; 206 matched sets. There was no difference in overall survival of matched cases and controls at 1 year (ML 83.7%, SL 90.2%), 3 years (ML 63.9%, SL 68%), and 5 years (ML 51.9%, SL 49.3%) (p=0.24). The CIs of receiving a lung transplant at 2 years for ML and SL were 83.6% and 71%, respectively. Multi-listing increased the probability of receiving a transplant (p<0.001) but was not associated with waitlist mortality (p=0.13). There was no difference in post-transplant survival between ML and SL candidates (HR=0.82, p=0.32). ML was associated with a substantial increase in probability of lung transplantation, but there was no difference in overall survival, post-transplant, or wait-list mortality. Our study permits more informed decision-making for patients considering the ML strategy.