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The ISHLT in Nice: Viewed Through the Eyes of One Heart Failure/Transplant Cardiologist

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Maryl R. Johnson, MD
University of Wisconsin
Madison, WI, USA

The ISHLT meetings in Nice provided a true potpourri of items of significant interest and importance to heart failure/transplant cardiologists. Although it is impossible to summarize the myriad presentations in a few paragraphs, some themes predominated and are worthy of highlighting (seasoned with a generous dose of personal opinion).

First, the burgeoning field of mechanical circulatory support versus the stable field of heart transplantation was clear. The functional benefits of LVAD implantation in patients with advanced heart failure continue to be shown, while the side effects (neurologic and bleeding in particular) continue to give us pause to expanding the use of LVADs to less ill patients. Fortunately, numerous presentations were aimed at trying to provide a basic understanding of the mechanisms of the complications that occur in VAD patients, which hopefully over time will allow a decrease in complications and more comfort in implanting VADs in less ill patients. In addition, one of the major benefits of our society, its international membership, provided the opportunity to compare and contrast VAD patient management strategies in centers around the world.

Two major VAD trials were presented at the meeting. The ROADMAP Study (Risk Assessment and Comparative Effectiveness of Left Ventricular Assist Device and Medical Management in Heart Failure Patients) was an observational study of the Thoratec HeartMate II LVAD compared to optimal medical management in patients with advanced heart failure. Thirty day mortality was the same in both groups (1%) while one year survival was 80% in the LVAD group compared to 64% in the medical group (on an as treated basis). Functional status and quality of life improved significantly more in the LVAD group (analyzed by 6 minute walk, health related quality of life, and NYHA class). Unfortunately, adverse events in the LVAD group remained similar to what was previously reported in the DT trial, with bleeding being the most frequent adverse event.

The ENDURANCE trial randomized patients eligible for DT 2:1 to the HeartWare centrifugal flow LVAD versus the HeartMate II axial flow LVAD. The trial did reach its primary noninferiority endpoint of stroke free survival at 2 years (55.0% in the HeartWare patients versus 57.4% in the HeartMate II patients). Of note, a change in the design of the HeartWare device during the trial (sintering of the inflow cannula) appeared to decrease the incidence of pump thrombosis. Overall, the stroke rate was higher in the HeartWare arm whereas device malfunctions requiring exchange or urgent transplantation were more common in the HeartMate II arm. Data analysis suggested that better blood pressure control in the HeartWare arm may decrease the stroke rate and a second cohort of patients is being enrolled with more attention being paid to blood pressures management.

A notable presentation regarded the possibility that the vWF degradation fragments in patients on continuous flow LVAD support may increase angiogenesis and angiodysplasia, a possible mechanism of the increased risk of GI bleeding. It was also of interest that many European centers do not routinely treat LVAD patients with aspirin, but only with vitamin K antagonists, and whether this would be adequate in the U.S. patient population where aspirin has more routinely been used is unclear.

Despite the rapid advances being made in mechanical circulatory support, heart transplantation remains the treatment of choice for patients with severe heart failure. However, the shortage of donor hearts and the number of sensitized patients on our waiting lists means that heart transplantation will never be the answer for all patients with end stage heart failure, even those deemed to be transplant candidates. Several presentations concerned approaches to the sensitized patient, including removal of antibody, prevention of antibody formation, blockade of the complement system, and immune modulation using IVIg, among others, but no consensus exists and timing the desensitization to take effect at a time a donor organ might be available is like trying to read tea leaves. The challenge is made even greater by the increased sensitivity of current assays to define the presence and strength of HLA antibodies, for which in many cases clinical relevance has not been clearly defined. Indeed, what does it truly mean if patients have negative cytotoxic crossmatches (which have allowed successful transplants for years) but virtual positive crossmatches based on solid phase assays? It raises the concern that by excluding donors based on more sensitive assays we may be doing our patients a disservice by excluding donor hearts that might work just fine.

An additional theme was heart allocation systems. Significant controversy remains regarding the appropriate priority for patients on implanted LVADs and with sensitization. Although LVADs can stabilize patients and allow hospital discharge, LVADs are not complication free and waiting until a patient has had a VAD complication to give them priority on the waiting list often results in a worse candidate for transplantation (i.e., one with a poorer outcome) or even precludes transplantation. For a sensitized patient, the donor pool is limited to donors who have antigens that are not felt to preclude successful transplantation, but under what circumstances (if any) should this give the sensitized patient the highest priority for a compatible donor, particularly with incomplete standardization of antibody detection techniques in different centers?

Presentations at the 2015 ISHLT Annual Scientific Sessions provided some answers to dilemmas we face daily in trying the optimize the outcomes of candidates for cardiac transplantation and those fortunate enough to become transplant recipients. However, they also brought to light even more areas where ongoing research is needed, and this is an equally important part of the meeting. To meet with colleagues from around the world and share our collective knowledge and challenges is a true strength of our society and its annual scientific sessions. I am already looking forward to next year's edition. ■

Disclosure Statement: The author has no conflicts of interest to disclose.

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