Weak Pump Function Predicts Poor Outcomes After Stenting in Heart Transplant Patients

For the thousands of people living with a donor heart, the greatest long-term threat is often not rejection but a silent, diffuse narrowing of the coronary arteries known as cardiac allograft vasculopathy. Because donor organs remain scarce, re-transplantation is rarely an option, so cardiologists frequently turn to percutaneous coronary intervention, or PCI, to prop open the failing vessels of the transplanted heart. A new study from Germany’s largest transplant center now shows that one simple, routinely measured number, the left ventricular ejection fraction, can predict with striking accuracy how those procedures will go and whether patients will still be alive three years later.

The research, published in Clinical Research in Cardiology, followed 159 heart transplant recipients who underwent PCI at the Heart and Diabetes Center North Rhine-Westphalia between January 2011 and June 2023. The team, led by Luisa Elbinger and Mohamed Ayoub of Ruhr University Bochum, divided patients according to their ejection fraction, the percentage of blood the left ventricle pumps out with each beat. Roughly two-thirds of the cohort had a preserved ejection fraction above 50 percent, while one-third, 52 patients, had a reduced value at or below that threshold. The median ejection fraction across the entire cohort was 55 percent, a figure that might look reassuring on a chart but concealed dramatic differences in outcome.

The technical details of the two groups tell a story about disease severity. Patients with reduced ejection fraction were, somewhat counterintuitively, younger, with a mean age of 54.1 years compared with 59.3 years in the preserved group, and they carried a higher body mass index. Their blood counts revealed more systemic stress: white cell counts were elevated, while hemoglobin and protective high-density lipoprotein cholesterol were lower. Most telling was the state of the graft’s arteries. Severe vasculopathy, classified as CAV grade III, affected nearly 81 percent of the reduced-ejection-fraction group but only about 45 percent of those with preserved function. Their SYNTAX II scores, a composite measure of coronary lesion complexity, were also significantly higher, with a median of 36.6 versus 28.6.

When the interventional results were tallied, the differences became unmistakable. Only 76.9 percent of patients with reduced ejection fraction achieved technical success, defined by the PROGRESS-CTO criteria as a residual narrowing below 30 percent with normal TIMI grade 3 blood flow, compared with 89.7 percent of those with preserved function. Procedural success, which additionally requires freedom from major adverse cardiac and cerebrovascular events during the hospital stay, fell to 75 percent in the reduced group against 89.7 percent in the preserved group. Fewer patients with weak grafts reached normal post-procedure flow, 76.9 versus 90.7 percent, and femoral access was used more often. After statistical adjustment for age, kidney function, hemoglobin, body mass index, rejection episodes and SYNTAX score, a reduced ejection fraction remained an independent predictor of both lower technical success, with an odds ratio of 0.350, and lower procedural success, with an odds ratio of 0.334.

The survival data were even more consequential. At three years, all-cause mortality reached 42.3 percent among patients with an ejection fraction of 50 percent or less, nearly double the 19.6 percent seen in those with better-preserved pump function. The excess risk was visible almost immediately: during the index hospitalization, 11.6 percent of the reduced group died compared with none of the preserved group, and by one year the figures were 38.5 versus 8.4 percent. In multivariable analysis, reduced ejection fraction carried an adjusted hazard ratio of 2.684 for three-year mortality, meaning these patients faced nearly a threefold higher risk of death even after accounting for other clinical variables.

The composite endpoint of major adverse cardiac and cerebrovascular events, which combines death, heart attack, stroke and repeat revascularization, followed the same pattern. The unadjusted three-year risk was significantly higher in the reduced-ejection-fraction group, with a hazard ratio of 1.915, and after adjustment the association persisted with a hazard ratio of 1.803. Notably, the mortality signal held up when ejection fraction was analyzed as a continuous variable: every one-percentage-point increase in ejection fraction was associated with a 4.4 percent relative reduction in the risk of death, a graded relationship that strengthens the case for causality rather than a mere threshold effect.

Stratifying patients by heart failure phenotype sharpened the picture further. Those with only mildly reduced ejection fraction, in the 41 to 49 percent range, already faced a 2.3-fold increased mortality risk, while patients with frankly reduced function of 40 percent or below had a 4.5-fold higher risk compared with those whose grafts pumped normally. Interestingly, neither prior rejection episodes nor a high SYNTAX score predicted adverse outcomes in the adjusted models, suggesting that the ejection fraction captures something about overall graft vulnerability that conventional risk markers miss. The authors propose that it functions as an objective indicator of clinical fragility in this uniquely complex population.

The biological backdrop helps explain these findings. Cardiac allograft vasculopathy differs from ordinary atherosclerosis in that it progresses diffusely and concentrically, driven by endothelial dysfunction and chronic inflammation that thicken the vessel intima and remodel the entire coronary tree. It often invades intramyocardial and distal segments that catheters simply cannot reach, which limits complete revascularization and may partly account for the lower success rates in sicker grafts. Previous work by Agarwal and colleagues showed that non-intervenable CAV grade 3 lesions carry a particularly poor prognosis, and that reduced ejection fraction below 45 percent independently predicts mortality, findings consistent with the new German data.

Importantly, the study also delivered a reassuring message about safety. Despite the higher-risk profile of patients with weak grafts, the investigators observed no cases of coronary perforation, pericardial effusion or bleeding complications in either group, supporting PCI as a feasible and safe option even in fragile transplant recipients. The authors caution, however, that their analysis was retrospective, single-center and based on a relatively small sample, that ejection fraction was measured at varying time points before intervention, and that not all patients completed three years of follow-up. Larger multicenter cohorts will be needed to validate the findings.

Even with those caveats, the implications for clinical practice are immediate. Ejection fraction is cheap, noninvasive and already obtained routinely during echocardiographic surveillance of every transplant patient, which means it can be folded into pre-procedural risk assessment without any additional testing. For the roughly one in three transplant recipients whose graft function has slipped below the 50 percent mark, the data argue for intensified monitoring and tailored post-procedural care, because in the transplanted heart, the pump’s strength is far more than a routine measurement. It is a window into the graft’s overall resilience and a powerful forecast of who will benefit from stenting, and who may need closer watch than anyone previously suspected.

Subject of Research: The prognostic impact of left ventricular ejection fraction on outcomes of percutaneous coronary intervention in heart transplant recipients with cardiac allograft vasculopathy

Article Title: Influence of left ventricular ejection fraction on the clinical outcome of percutaneous coronary interventions in heart transplant patients

Article References: Elbinger, L., Schupp, T., Behnes, M., Akin, I., Costard-Jäckle, A., Schramm, R., Rudolph, T., Rudolph, V., & Ayoub, M. (2026). Influence of left ventricular ejection fraction on the clinical outcome of percutaneous coronary interventions in heart transplant patients. Clinical Research in Cardiology. https://doi.org/10.1007/s00392-026-03032-z

Image Credits: AI Generated

DOI: 10.1007/s00392-026-03032-z

Keywords: heart transplantation, cardiac allograft vasculopathy, percutaneous coronary intervention, left ventricular ejection fraction, PCI outcomes, all-cause mortality, MACCE, prognosis, cardiology, graft dysfunction, SYNTAX score, transplant cardiology