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Left ventricular assist device (LVAD) implantation in patients with advanced heart failure due to hypertrophic or restrictive cardiomyopathy (HCM/RCM) presents technical and physiologic challenges. We conducted a systematic review of observational studies to evaluate the utilization and clinical outcomes associated with LVAD implantation in patients with HCM/RCM and compared these to patients with dilated or ischemic cardiomyopathy (DCM/ICM). We searched MEDLINE, EMBASE, and Scopus from inception through May 2019 and included appropriate studies describing the use of an LVAD in patients with HCM/RCM. We identified six studies with a total of 2,766 patients with HCM/RCM and advanced heart failure, among whom 338 patients (12.2%) underwent LVAD implantation. In patients listed for transplant, the rate of LVAD implantation was significantly lower in patients with HCM/RCM compared to that in patients with DCM/ICM (4.4% vs. 18.2%, p < 0.001). Adverse clinical outcomes were significantly higher in HCM/RCM than in DCM/ICM, including operative/short-term mortality (14.0% vs. 9.0%), right ventricular failure (50.0% vs. 21.0%), infection (15.5% vs. 11.2%), bleeding (40.2% vs. 12.5%), renal failure (15.0% vs. 5.1%), stroke (5.0% vs. 2.4%), and arrhythmias (18.0% vs. 7.7%) (all p values <0.001).

Purpose: In October 2018, a new US adult heart allocation scheme was enacted in which the etiology of cardiomyopathy can play a significant role in the prioritization of patients listed for transplantation. Given this, we embarked on a review of the diagnoses of patients who underwent therapy for advanced heart failure at our center.
Method(s): We retrospectively reviewed the etiology of cardiomyopathy of patients receiving either durable ventricular assist device (VAD) or orthotopic heart transplantation (OHT) at NYU Langone Medical Center in New York, NY between January 2011 and October 2018. We evaluated for discrepancies between the primary HF diagnosis at time of operation with the ultimate diagnosis, combining both clinical follow-up data and cardiac pathology.
Result(s): During the study period, a total of 110 patients were treated with advanced therapies, of which the majority (74.5%) were male. 40.9% were African American, 35.4% Caucasian, 4.5% Asian, and 23.6% Hispanic. 86.3% underwent VAD and 22.0% underwent OHT. The average age of those undergoing OHT and VAD were 58 and 61 respectively. The most common reported etiology of HF was dilated cardiomyopathy (57.3%), followed by ischemic (36.3%), familial DCM (1.8%), amyloidosis (1.8%), restrictive cardiomyopathy (1.8%), and sarcoidosis (0.9%). On final review of the diagnoses in these patients, 14 (12.7%) had a final diagnosis that was inconsistent with the prior reported one. 5 were clerical errors, but 9 were significant deviations from the prior diagnosis. The most common diagnoses that were misidentified prior to VAD or OHT were cardiac sarcoidosis (2), cardiac amyloidosis (2), and hypertrophic cardiomyopathy (2). Among those 9 patients, 7 patients received VAD with 5 eventually requiring OHT (median days to OHT = 248); 2 patients directly received OHT. All of those are alive except one patient who was lost to follow-up (transferred care to another center). Patients in whom the diagnosis was misidentified prior to VAD or OHT had smaller LV dimensions on transthoracic echocardiography on average than other LVAD or OHT patients with non-ischemic cardiomyopathy.
Conclusion(s): In this single-center review, we found that the majority of HF patients undergoing VAD and OHT had a correct diagnosis for their heart failure prior to treatment, although notably 8.1% had a missed diagnosis at time of intervention (VAD or OHT). Appropriately identifying the subtype of cardiomyopathy remains challenging especially in advanced HF patients but can significantly impact waiting list time in the current organ allocation scheme. A normal or minimally increased LV dimension on echocardiogram in a patient with advanced non-ischemic cardiomyopathy may warrant further workup for another diagnosis.
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