Preprocedural Computed Tomography Planning for Surgical Aortic Valve Replacement.

BACKGROUND: Selection of transcatheter valve size using preprocedural computed tomography (CT) is standardized and well established. However, valve sizing for surgical aortic valve replacement (SAVR) is currently performed intraoperatively by using sizers, which may result in variation among operators and risk for prosthesis-patient mismatch. This study evaluated the usefulness of CT annulus measurement for SAVR valve sizing. METHODS: This study included patients who underwent SAVR using Inspiris or Magna Ease and received preoperative electrocardiogram-gated CT imaging. Starting from June 2022, study investigators applied a CT sizing algorithm using CT-derived annulus size to guide minimum SAVR label size. The final decision of valve selection was left to the operating surgeon during SAVR. The study compared the appropriateness of valve selection (comparing implanted size with CT-predicted size) and prosthesis-patient mismatch rates without aortic root enlargement between 2 cohorts: 102 cases since June 2022 (CT sizing cohort) and 180 cases from 2020 to 2021 (conventional sizing cohort). RESULTS: Implanted size smaller than CT predicted size and severe prosthesis-patient mismatch were significantly lower by CT sizing than by conventional sizing (12% vs 31% [P = .001] and 0% vs 6% [P = .039], respectively). Interoperator variability was a factor associated with implanted size smaller than CT predicted with conventional sizing, whereas it became nonsignificant with CT sizing. CONCLUSIONS: Applying CT sizing to SAVR led to improved valve size selection, less prosthesis-patient mismatch, and less interoperator variability. CT sizing for SAVR could also be used to predict prosthesis-patient mismatch before SAVR and identify patients who need aortic root enlargement.

The impact of obesity on cardiac surgery outcomes.

BACKGROUND: A survival benefit for obese patients has been observed in various medical and surgical populations. We examined the effect of obesity on outcomes after cardiac surgery from a large national database. METHODS: A total of 6 648 334 adult patients were identified from the Nationwide Inpatient Sample who underwent cardiac surgery between 1998 and 2011, of who 598 450 were obese. Multivariable regression analysis and propensity score matching were used for comparisons of outcomes and costs. RESULTS: In-hospital mortality was 2.0% for obese patients versus 2.3% for non-obese patients (odds ratio [OR] 0.89, 95% confidence interval [CI] 0.84, 0.94). Obese patients were at increased risk for acute renal failure (OR, 1.20; CI, 1.16, 1.23) and wound infection (OR, 1.29; CI, 1.18, 1.40), but less likely to require blood transfusion (OR, 0.96; CI, 0.94, 0.98). Mean length of stay was the same (8.7 days), with greater mean total charges for obese patients ($103 645 vs $101 763, P < 0.001). CONCLUSION: Obesity is associated with lower in-hospital mortality rates, but a higher incidence of acute renal failure and wound infections.

Staged repair of thoracoabdominal aneurysm with infra-renal elephant trunk graft.

A patient with residual thoracoabdominal aortic aneurysm and chronic dissection extending into the branch iliac arteries underwent staged open and endovascular repair. Open repair of the reno-visceral segment was performed with an "elephant trunk" trunk graft placed distally into a 12-cm infra-renal aorta. One month later, the patient underwent a successful completion endovascular aortic repair. This case demonstrates the utility of combining traditional and endovascular surgery to manage complex aortic pathologies.

Devices for ex vivo heart and lung perfusion.

INTRODUCTION: The number of organs available for heart and lung transplantation is far short of the number that is needed to meet demand. Perfusion and ventilation of donor organs after procurement has led to exciting advances in the field of cardiothoracic transplantation. The clinical implications of this technology allows for techniques to evaluate the quality of an organ, active rehabilitation of organs after procurement and prior to implantation, and increased time between organ procurement and implantation. This ex-vivo perfusion technique has also been referred to in the lay press as the 'heart in a box' or 'lung in a box.' AREAS COVERED: This review includes information from case reports, case series, and clinical trials on ex vivo heart and lung perfusion. The focus is on the devices, ventilation and perfusion techniques, outcomes, and application of the technology. EXPERT COMMENTARY: Ex vivo perfusion of donor hearts and lungs prior to transplantation has proven to be a viable alternative to standard cold-preservation strategies. Its use has allowed for ongoing expansion of the donor pool. The biggest barriers to expansion of this technology are access, cost, and lack of evidence which clearly supports superior outcomes.

Impact of Cirrhosis in Patients Who Underwent Surgical Aortic Valve Replacement.

Cirrhosis is known to adversely affect cardiac surgery outcomes. Our objective was to quantify the morbidity, mortality, and cost that cirrhosis adds to surgical aortic valve replacement. From 1998 to 2011, 423,789 patients in the Nationwide Inpatient Sample Healthcare Cost Utilization Project underwent isolated aortic valve replacement; 2,769 (0.7%) had cirrhosis. Multivariable linear regression and 1:1 propensity matching were used to determine the effect of cirrhosis on postsurgical outcomes. The number of patients with cirrhosis who underwent surgical aortic valve replacement per year more than tripled during the 13-year study period. Patients with cirrhosis were more likely to be younger (p <0.0001), insured by Medicaid (p <0.0001), and operated on at an academic or high-volume hospital (p <0.05). Risk-adjusted mortality for patients with cirrhosis was 16%, compared with 5% for patients without cirrhosis. Risk factors for death included congestive heart failure, fluid and electrolyte imbalances, pulmonary circulation disorders, and weight loss. Among propensity-matched pairs, patients with cirrhosis had a higher mortality (odds ratio [OR] 3.6), risk of any complication [OR 1.5], and acute renal failure (OR 2.2). There was no increased risk of stroke, wound infection, blood transfusion, or pneumonia. The risk-adjusted length of stay (15 vs 12 days) and cost ($68,000 vs 56,000) were higher in patients with cirrhosis. In conclusion, the presence of cirrhosis poses a significant risk of death in patients who underwent surgical aortic valve replacement. When performed, the cost and length of stay are increased compared with those without cirrhosis.

Optimal Timing of Heart Transplant After HeartMate II Left Ventricular Assist Device Implantation.

BACKGROUND: Optimal timing of heart transplantation in patients supported with second-generation left ventricular assist devices (LVADs) is unknown. Despite this, patients with LVADs continue to receive priority on the heart transplant waiting list. Our objective was to determine the optimal timing of transplantation for patients bridged with continuous-flow LVADs. METHODS: A total of 301 HeartMate II LVADs (Thoratec Corp, Pleasanton, CA) were implanted in 285 patients from October 2004 to June 2013, and 86 patients underwent transplantation through the end of follow-up. Optimal transplantation timing was the product of surviving on LVAD support and surviving transplant. RESULTS: Three-year survival after both HeartMate II implantation and heart transplantation was unchanged when transplantation occurred within 9 months of implantation. Survival decreased as the duration of support exceeded this. Preoperative risk factors for death on HeartMate II support were prior valve operation, prior coronary artery bypass grafting, low albumin, low glomerular filtration rate, higher mean arterial pressure, hypertension, and earlier date of implant. Survival for patients without these risk factors was lowest when transplant was performed within 3 months but was relatively constant with increased duration of support. Longer duration of support was associated with poorer survival for patients with many of these risk factors. Device reimplantation, intracranial hemorrhage, and postimplant dialysis during HeartMate II support were associated with decreased survival. CONCLUSIONS: Survival of patients supported by the HeartMate II is affected by preoperative comorbidities and postoperative complications. Transplantation before complications is imperative in optimizing survival.

Mechanical circulatory support in pediatrics.

End-stage heart failure affects thousands of children yearly and mechanical circulatory support is used at many points in their care. Extracorporeal membrane oxygenation supports both the failing heart and lungs, which has led to its use as an adjunct to cardiopulmonary resuscitation as well as in post-operative cardiogenic shock. Continuous-flow ventricular assist devices (VAD) have replaced pulsatile-flow devices in adults and early studies have shown promising results in children. The Berlin paracorporeal pulsatile VAD recently gained U.S. Food and Drug Administration approval and remains the only VAD approved in pediatrics. Failing univentricular hearts and other congenitally corrected lesions are new areas for mechanical support. Finding novel uses, improving durability, and minimizing complications are areas of growth in pediatric mechanical circulatory support.

Human Fitting Studies of Cleveland Clinic Continuous-Flow Total Artificial Heart.

Implantation of mechanical circulatory support devices is challenging, especially in patients with a small chest cavity. We evaluated how well the Cleveland Clinic continuous-flow total artificial heart (CFTAH) fit the anatomy of patients about to receive a heart transplant. A mock pump model of the CFTAH was rapid-prototyped using biocompatible materials. The model was brought to the operative table, and the direction, length, and angulation of the inflow/outflow ports and outflow conduits were evaluated after the recipient's ventricles had been resected. Thoracic cavity measurements were based on preoperative computed tomographic data. The CFTAH fit well in all five patients (height, 170 ± 9 cm; weight, 75 ± 24 kg). Body surface area was 1.9 ± 0.3 m (range, 1.6-2.1 m). The required inflow and outflow port orientation of both the left and right housings appeared consistent with the current version of the CFTAH implanted in calves. The left outflow conduit remained straight, but the right outflow direction necessitated a 73 ± 22 degree angulation to prevent potential kinking when crossing over the connected left outflow. These data support the fact that our design achieves the proper anatomical relationship of the CFTAH to a patient's native vessels.

Does pulsatility matter in the era of continuous-flow blood pumps?

Despite significant improved survival with continuous flow left ventricular assist devices (LVADs), complications related to aortic valve insufficiency, gastrointestinal bleeding, stroke, pump thrombosis, and hemolysis have dampened the long term success of these pumps. Evolution has favored a pulsatile heart pump to be able to deliver the maximum flow at different levels of systemic vascular resistance, confer kinetic energy to the flow of blood past areas of stenosis and generate low shear stress on blood elements. In this perspective, we suggest that lack of pulsatility may be one factor that has limited the success of continuous flow LVADs and suggest that research needs to focus on methods to generate pulsatility either by the native heart or by various speed modulation algorithms.

Using near-infrared spectroscopy to monitor lower extremities in patients on venoarterial extracorporeal membrane oxygenation.

Patients on peripheral extracorporeal membrane oxygenation (ECMO) are at risk for lower extremity ischemia. Effective monitoring is needed to identify complications quickly and allow timely correction. Near-infrared spectroscopy has been used extensively in cerebral monitoring during cardiac surgery. We present its use in monitoring lower extremity perfusion in patients on ECMO. Five patients on ECMO had near-infrared spectroscopy monitors placed on the calf of both lower extremities. Continuous real-time tissue oxygen saturation data (stO2) was displayed and recorded. Two patients had lower extremity complications in the leg with the arterial cannula. The patients with complications had lower stO2 in the cannulated leg at the time of ECMO insertion, larger differences in stO2 between the legs at the time of insertion, lower nadir stO2s, and larger peak differences in stO2 between the legs than patients without limb complications. The use of near-infrared spectroscopy for continuous monitoring of tissue oxygenation in the lower extremities in patients on ECMO may allow early identification of patients with lower extremity complications.

Mechanical circulatory support for the right ventricle in the setting of a left ventricular assist device.

Right ventricular failure is a difficult problem to manage and typically carries a dismal prognosis. In the setting of post-left ventricular assist device implantation (LVAD), right ventricular dysfunction both in the early and late stages is of particularly high incidence and concern. There are currently no agreed upon preoperative algorithms to predict patients at risk for this problem, thus adding another level of complexity to treatment. Furthermore, there is no current technology available for chronic right ventricular support and the devices currently in use are LVADS modified to adapt to the right circulatory system. This review provides an overview of right ventricular failure, particularly after LVAD implantation, and describes the survival outcomes and continued challenges in this area.

Lessons learned from the first fully magnetically levitated centrifugal LVAD trial in the United States: the DuraHeart trial.

BACKGROUND: The DuraHeart is a continuous centrifugal-flow left ventricular assist device that uses active magnetic levitation for impeller positioning designed for improved hemocompatibility and durability. This study reviews the results of the US trial with specific attention to hemolysis, thrombotic complications, and pump failure. METHODS: The US SUSTAIN trial was a multicenter, prospective, single-arm observational study in advanced heart failure patients listed for transplantation. Follow-up was complete in 100% of the patients at 6 months. RESULTS: Sixty-three patients were enrolled at 23 centers. Forty-six patients (73%) reached the primary end points of survival to transplantation, alive on the original device at 180 days and listed for transplantation, or explant for recovery. Median duration of support was 267 days (range, 10 to 952 days) with a total support time of 46 patient-years. There was no clinical hemolysis reported during the study. Mean lactate dehydrogenase values peaked at day 4 and significantly decreased during support (435±236 U/L and 297±142 U/L on day 3 and day 180, respectively). There were no cases of pump thrombosis reported, and 3 cases of pump thrombus "in transit" (0.06 events/patient-year) were observed. There were 6 (10%) cases of magnetic levitation system failure, all secondary to cable wire fractures (0.12 events/patient-year). All patients were hemodynamically stable with the backup hydrodynamic mode. Major adverse events included gastrointestinal bleeding (0.52 events/patient-year), ischemic and hemorrhagic strokes (0.17 events/patient-year and 0.09 events/patient-year, respectively), and driveline infections (0.67 events/patient-year). CONCLUSIONS: The DuraHeart demonstrated good hemocompatibility; however, the reliability of full magnetic levitation systems should be a high priority in future pump designs.