Impact Of Variation Of Donor Heart Left Ventricular Size On The Outcomes After Orthotopic Heart Transplant

Background Negative effects of the mismatch of donor-to-recipient heart size during the orthotopic heart transplantation (OHT) are well known. At the same time, very few studies looked at the prognostic value of changes occurring with the size of the donor heart post transplant. Aim To evaluate the change in the post-transplant left ventricle (LV) size of the donor heart in recipient and its impact on outcomes. Methods This was a retrospective study among patients who underwent OHT between Jan 2015 and Sept 2020 at a single institution. Patients were excluded if they were<18 years old, received OHT for congenital heart disease, had follow-up<6 months or missing donor variables. We collected donor and recipient demographics, comorbidities, reason for OHT, donor pre-OHT echo and right heart catheterization (RHC) parameters. First and last echocardiograms post OHT were collected at least 6 months apart. Donor data was extracted from the United Network for Organ Sharing database. Patients were divided into two groups: survivors and non-survivors. Primary outcome was the variation in donor heart size evaluated immediately after the transplant and at the last follow-up , secondary outcome was heart failure (HF) admissions. T-test was used to compare variables between the two groups. Linear regression was used to adjust for age and body mass index (BMI). Statistical analysis was performed using Stata 15.1. Results Among 156 reviewed patients, N=71 were included after excluding 85 patients. The recipients median age was 58 ±14 y, 31% were Female (F), 20% were African-American (AA) while donors median age was 33±11y; 24% were F, 20% were AA. OHT allocation was male to male (64%) female to female (19%); female to male (4%); male to female (13%). The duration of follow-up was up to 6 years and 24% (N=17/71) of patients did not survive. There was no difference in age, gender, race yet BMI was significantly higher among non-survivors (30.10 ± 3.65 vs 27.79 ± 3.74 kg/m2; p=0.028). By predicted heart mass (PHM), the right ventricular mass was similar in survivors and non-survivors, whereas left ventricular (LV) mass was higher among patients who died without reaching statistical significance (169.14 ± 31.8 vs 154.44 ± 30.5; p=0.09). There was no difference in survivors vs non-survivors in etiology of HF, coronary artery disease, arrhythmia, medical therapy, echo or RHC variables, yet non-survivors had higher prevalence of pre-OHT pacemaker (35% vs 11%; p=0.02). There was no difference in PHM ratio between non-survivors and survivors (1.04 ± 0.18 vs 1.01 ± 0.17; p=0.53). Non-survivors had a trend to a decrease in LVEDD (LV end diastolic diameter) at first echo after transplant (-15.11% ± 37.57 vs -1.04% ± 22.19;p=0.07), and a significant decrease in LVEDD at last follow-up (-18.54% ± 34.13 vs -3.75% ± 14.93;p=0.019). There was a trend towards more HF admissions among non survivors without reaching statistical significance (35% vs 15%;p=0.06) . Conclusion This is the first study to suggest significant impact of change in LV size on post OHT outcomes. A post-transplant decrease in the size of the LV was associated with a lower survival. Negative effects of the mismatch of donor-to-recipient heart size during the orthotopic heart transplantation (OHT) are well known. At the same time, very few studies looked at the prognostic value of changes occurring with the size of the donor heart post transplant. To evaluate the change in the post-transplant left ventricle (LV) size of the donor heart in recipient and its impact on outcomes. This was a retrospective study among patients who underwent OHT between Jan 2015 and Sept 2020 at a single institution. Patients were excluded if they were<18 years old, received OHT for congenital heart disease, had follow-up<6 months or missing donor variables. We collected donor and recipient demographics, comorbidities, reason for OHT, donor pre-OHT echo and right heart catheterization (RHC) parameters. First and last echocardiograms post OHT were collected at least 6 months apart. Donor data was extracted from the United Network for Organ Sharing database. Patients were divided into two groups: survivors and non-survivors. Primary outcome was the variation in donor heart size evaluated immediately after the transplant and at the last follow-up , secondary outcome was heart failure (HF) admissions. T-test was used to compare variables between the two groups. Linear regression was used to adjust for age and body mass index (BMI). Statistical analysis was performed using Stata 15.1. Among 156 reviewed patients, N=71 were included after excluding 85 patients. The recipients median age was 58 ±14 y, 31% were Female (F), 20% were African-American (AA) while donors median age was 33±11y; 24% were F, 20% were AA. OHT allocation was male to male (64%) female to female (19%); female to male (4%); male to female (13%). The duration of follow-up was up to 6 years and 24% (N=17/71) of patients did not survive. There was no difference in age, gender, race yet BMI was significantly higher among non-survivors (30.10 ± 3.65 vs 27.79 ± 3.74 kg/m2; p=0.028). By predicted heart mass (PHM), the right ventricular mass was similar in survivors and non-survivors, whereas left ventricular (LV) mass was higher among patients who died without reaching statistical significance (169.14 ± 31.8 vs 154.44 ± 30.5; p=0.09). There was no difference in survivors vs non-survivors in etiology of HF, coronary artery disease, arrhythmia, medical therapy, echo or RHC variables, yet non-survivors had higher prevalence of pre-OHT pacemaker (35% vs 11%; p=0.02). There was no difference in PHM ratio between non-survivors and survivors (1.04 ± 0.18 vs 1.01 ± 0.17; p=0.53). Non-survivors had a trend to a decrease in LVEDD (LV end diastolic diameter) at first echo after transplant (-15.11% ± 37.57 vs -1.04% ± 22.19;p=0.07), and a significant decrease in LVEDD at last follow-up (-18.54% ± 34.13 vs -3.75% ± 14.93;p=0.019). There was a trend towards more HF admissions among non survivors without reaching statistical significance (35% vs 15%;p=0.06) . This is the first study to suggest significant impact of change in LV size on post OHT outcomes. A post-transplant decrease in the size of the LV was associated with a lower survival.