Concomitant MAZE procedure during cardiac surgical procedures: is there any survival advantage in conversion to sinus rhythm?

AIM: The MAZE procedure, or concomitant intraoperative ablation, is an effective technique to restore long-term sinus rhythm (SR). The survival benefit of conversion to SR has been questioned recently. METHODS: We retrospectively evaluated the conversion rate to SR and its correlation with long-term survival in 209 patients with chronic AF, who had a MAZE procedure during cardiac surgical procedures between the years 2006 and 2011 at our institution. The mean age was 67.2 ± 12.0 years and 52.2% were female (N. = 109). Perioperative mortality was 5.74% (N. = 12). RESULTS: In univariate analysis, significant risk factors for perioperative mortality were age (P = 0.0033), duration of perfusion time (P = 0.0093), elevated creatinine (≥ 1.6 mg/dL, P = .02), and cross clamp time (P = 0.016). In multivariate analysis age (HR 2.97) and duration of perfusion time (HR 1.48) were the only independent predictors of perioperative mortality. The overall one and five-year survival rates were 88% ± 2.2%, and 76% ± 3.3%, respectively. The one and five-year survival rates for patients who converted and were in sinus rhythm (SR) upon discharge (N. = 154) were 88% ± 2.6% and 80% ± 3.5%, respectively. While the one and five-year survival rates for patients who were still in AF upon discharge (N. = 55) were 94% ± 3% and 82% ± 6.6%, respectively, this survival difference was not statistically significant (P = 0.24). Significant risk factors for long-term mortality included DM (P = 0.023), preoperative MI (P = 0.043), preoperative renal insufficiency (creatinine, ≥ 1.6 mg/dL, P = 0.02) and asthma/COPD (P = 0.040). In multivariate analysis, age (HR 1.048) and preoperative MI (HR 1.948) were the only independent predictors of long-term mortality. CONCLUSION: The surgical MAZE procedure has a high conversion rate, however, our data did not show improved survival in patients who converted to SR prior to discharge.

Left ventricular assist device exchange for persistent infection: a case series and review of the literature.

Left ventricular assist device (LVAD) exchange for control of infection may be an option for the treatment of persistent and severe infections of the LVAD. Data are limited regarding the indications for device exchange, methods for exchanging infected devices, post-exchange antimicrobial management, and outcomes of such patients. We report a series of cases in which an exchange was performed for persistent LVAD infection, review the literature on LVAD exchange and surgical techniques for these infectious complications, and suggest management strategies from a multidisciplinary perspective.

Ethical issues in living renal donation.

The widespread success of living renal transplantation has given the medical community both the opportunity and the responsibility of establishing social and ethical guidelines for the protection of donors and the treatment of recipients. While the prospects of treating more patients with organ transplant is exciting, the demand still far outpaces the supply. It is the responsibility of the transplant community and individual transplant centers to maintain a high level of integrity and ethical practice so that living renal transplantation can continue to be a viable and effective treatment for renal failure.

Current options for mechanical heart technology.

Heart transplantation remains the treatment of choice for end-stage heart failure despite limited donor availability and allograft durability. Artificial heart technology was initially developed as a replacement for transplantation but the initial experience with these technologies was disappointing. The quest for a total artificial heart has largely been abandoned in favor of ventricular assist devices (VADs). VADs have gained widespread acceptance as bridge to transplant and bridge to recovery therapy. After more than a decade of clinical use, several FDA approved device designs have proved effective in treating patients with various causes of heart failure. This review describes the current, clinically available ventricular replacement and assist devices and defines the adult patient populations in which they are useful. The next generation of these devices will soon become available and their clinical utility will likely shape the future direction of heart failure therapy. Ultimately the concept of a long-term total artificial heart may be revisited.

Venoarterial shunting for the treatment of right sided circulatory failure after left ventricular assist device placement.

Right sided circulatory failure (RSCF), a common complication after left ventricular assist device (LVAD) implantation, results in decreased systemic output due to diminished blood flow across the pulmonary vasculature. The authors hypothesized that creation of a venoarterial shunt (VAS) would decompress the right-sided circulation and improve systemic pressure and perfusion with significant arterial desaturation. An experimental model was created in which RSCF was induced acutely in a large animal (n = 6) by beta-blockade after LVAD placement. After VAS creation, hemodynamic and blood gas determinations were performed to compare non shunt and shunt states. After induction of heart failure after LVAD placement, VAS resulted in a 22% elevation in systemic blood pressure (p < 0.0001), a 36% elevation in cerebral blood flow (p = 0.02), and an 18% decrease in right sided filling pressures (p = 0.08). Systemic pH and aortic oxygen saturation remained unchanged from baseline. In a large animal model of RSCF after LVAD implantation, VAS improves systemic hemodynamics without a significant cost in arterial oxygenation to critical organs and without creating acid-base imbalance. Beside implementation, adjustable capabilities, easy removal and salutatory hemodynamic effects suggest that VAS may serve as a first line, short-term therapy for LVAD recipients who develop perioperative RSCF.

Validation study of a new transit time ultrasonic flow probe for continuous great vessel measurements.

Continuous measurement of cardiac output is important during experimental and clinical cardiac surgery as an indicator of ventricular function. Previous flow probes underestimated flow secondary to position and flow (S-series probes; Transonic Systems, Inc., Ithaca, NY), required frequent calibrations (electromagnetic), and were cumbersome to use. The new A-series probe (ASP) by Transonic Systems, Inc., uses a new X method of ultrasonic illumination insensitive to perturbations in flow. The ASPs were found to be accurate during in vitro studies, but have not been validated in vivo. Six anesthetized pigs were instrumented for right atrium to left atrium bypass, and ASPs were placed on the ascending aorta and pulmonary artery. Baseline measurements included aortic (Ao) and pulmonic flow (P), and thermodilution (Td) cardiac output. Animals then were placed on right heart bypass, and flow was randomly varied from 1 to 6 L/min, and Ao flow was recorded. In addition, ASPs were rotated and their direction reversed. After data collection, the occlusive roller pump (RP) was calibrated using a timed collection method. Calibrated RP flows were plotted versus ASP flows, and regression was applied. There was no difference between mean Ao, P, and Td cardiac outputs at baseline. In addition, changes in position and direction of the probe did not affect measurement of flow. The ASPs showed a highly linear correlation with RP ([r = 0.98, p < 0.01] ASP[L/min] = 0.98 RP-0.032). During laminar flow states, ASPs are accurate and insensitive to position on the great vessels.