American Heart Association
Frustrated by limited, single small center risk scores for RV failure? Kiernan and colleagues analyzed the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) to identify factors associated with RV failure following continuous flow left ventricular assist device (CF-LVAD) support.
Bleeding and thrombosis account for almost half of adverse events in patients with CF-LVADs.
Saeed et al analyzed 144 HeartMate II (HMII) CF-LVAD patients in a single center, retrospective study. Patients in the sildenafil groups were on sildenafil for pulmonary hypertension or right ventricular dysfunction for at least 30 days after discharge from CF-LVAD implant. Patients were divided into four groups:
Status 1A heart transplant candidates are critically-ill patients requiring mechanical circulatory support (MCS) or high-dose / multiple inotrope therapy to maintain perfusion. Status 1A candidates are listed as highest priority, and are thus more likely to receive a heart transplant. In 2006, a significant change occurred in the Organ Procurement and Transplantation Network (OPTN) criteria with the intent of increase geographic sharing. Following the update, organs were shared within a 500-mile radius as opposed to offers first being made to all candidates (Status 1A, 1B and 2) within local organ procurement organization.
Parker and colleagues investigated whether this policy change affected clinical practice patterns in care of patients listed for heart transplant. The bottom line: following the policy change transplanted patients were more likely to be on low dose inotropes.
Using the Scientific Registry of Transplant Recipients (SRTR) a comparison was made between heart transplant candidates pre (7/2000-7/11/2006) and post (7/12/2006-7/2015) geographic sharing.Status 1A candidates had the following values analyzed: hemodynamic data, MCS type, inotrope type(s) and doses.Between 2000 and 2006, the number of 1A candidates declined from 656 (22% of total candidates) to 452 (18%). However, from 2006-2015, 965 (26%) candidates were Status 1A. The same trend is seen in 1B candidates as well. Not surprisingly, Status 2 candidates steadily declined from 2000-2015 (1,673, 55% to 1,038, 28%).
Among Status 1A candidates, the inotrope subgroup (candidates without MCS) decreased in the pre-sharing era (256, 11% to 174, 8%), but significantly increased in the post-sharing era (381, 18% in 2015, p<0.001). Specifically, multiple-inotrope therapy increased substantially, with 153 more multiple-inotrope 1A candidates in 2015 compared to 2005 (p<0.001). The mean dose of inotropes within the multiple-inotrope subgroup was lower in the post-sharing era compared to the pre-sharing era (dobutamine dose decreased 49%, dopamine dose decreased 55%, and milrinone dose decreased 29%, p<0.001). Interestingly, the cardiac index slightly increased (2.17 to 2.25 L/min/m2, p=0.044).
The single, high-dose inotrope 1A subgroup had relatively stable dosing of milrinone (p=0.063) and a decrease of dobutamine by 4%, p<0.005. Of note, milrinone was used more frequently in the post-sharing era, with a 10% increase in frequency, p<0.001.
The waitlist survival of 1A candidates also increased in the post-sharing era. In the pre-sharing era, 1A candidates had a 130% higher chance of dying, while in the post-sharing era 1A candidates had a 33% higher chance of dying in comparison to Status 2 candidates. This shift represents a 62% risk reduction in death (comparing the last three years of pre-sharing with 7/12/2006-12/31/2010).
No study is perfect. Not all advanced heart failure patients are included in the SRTR, and although hemodynamic data was provided, there may be other factors not listed contributing to the use of multiple inotropes. Improvements in heart failure medical therapy may also contribute to improved waitlist survival of 1A candidates.
Worth noting, there were 220 more CF-LVAD 1A candidates in 2015 compared to 2005 (p<0.001), which certainly contributed to the growing number of 1A candidates as well.
Study Link: Trends in the Use of Inotropes to List Adult Heart Transplant Candidates at Status 1A
Bonus Points: December 2016 Proposal for six-status allocation system
CF-LVAD patients experience high rates of gastrointestinal (GI) bleeding. A multicenter, retrospective analysis by Shah et al demonstrated that patients with a prior GI bleed after CF-LVAD implantation had a lower rate (24% vs 43%) of recurrent GI bleed when receiving octreotide.
Fifty-one patients were identified from 5 participating centers. All patients had one previous GI bleed following CF-LVAD implantation, and received octreotide treatment for at least 6 months following index GI bleed. Octreotide was dosed as a monthly depot injection in 72% of patients or twice daily subcutaneous injection in 28%. Shah et al used a comparison group of HMII CF-LVAD patients who had experienced a GI bleed in clinical trials using HMII bridge-to-transplant (BTT) and destination therapy (DT). Patients were propensity matched based on HF etiology, CF-LVAD indication, CF-LVAD support time, sex, and age. Of the 51 CF-LVAD patients analyzed, 50% were DT. Twelve patients (24%) who received octreotide experienced a recurrent bleed vs 22 (43%) of the comparison group (p<0.04).
Decoupling of diastolic pulmonary artery pressure and PCWP (greater than 5 mmHg difference) during ramp testing in continuous flow LVAD patients is a significant predictor for HF hospitalization and all-cause mortality. This decoupling is also represented as the diastolic pressure gradient (dPAP-PCWP). dPAP and PCWP decoupling (increased DPG) may indicate intrinsic pulmonary vascular pathology and associated right ventricular strain.