Cardiopulmonary health risks among survivors of hematopoietic stem cell transplantation: a population-based cohort study

Background Haematopoietic cell transplantation (HSCT) is a critical treatment for patients with blood cancers and immunological or metabolic conditions. Improved survival has led to a growing population of long-term survivors in whom cardiovascular and pulmonary complications are increasingly recognised Purpose This study aimed to: i) evaluate the long-term risk of incident cardiovascular and pulmonary complications among HSCT recipients, ii) characterise subclinical cardiac and pulmonary phenotypes using cardiovascular magnetic resonance (CMR) imaging and spirometry, and iii) identify transplant- and patient-related predictors of cardiopulmonary outcomes. Methods We conducted a population-based cohort study using the UK Biobank. Adults undergoing a first autologous or allogeneic HSCT were identified and propensity score-matched to general population controls based on demographic, socioeconomic, lifestyle and clinical characteristics. Follow-up commenced on the date of transplantation for HSCT recipients and on the same date for corresponding matched controls. Incident disease-specific cardiovascular and pulmonary outcomes were ascertained using linked hospital admission and mortality records. Cause-specific Cox proportional hazards regression, stratified by matched set, was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). Imaging phenotypes were compared between groups using regression models that accounted for the matched design. Predictors of adverse cardiopulmonary outcomes were analysed using multivariable Cox models. Results The study cohort included 780 HSCT recipients and 3,120 matched general population controls (average age at transplant of 63.3 years; 59% male). 72.3% underwent autologous transplants, with peripheral blood stem cells as the predominant graft source (93.5%). Over a median prospective follow-up of 4.3 years, HSCT recipients had more than a threefold increased risk of cardiovascular disease, with the greatest risks observed for pericardial disease (HR 5.83 [2.81, 12.12]), venous thromboembolism (HR 5.36 [3.38, 8.49]) and heart failure (HR 3.32 [2.27, 4.87]). Pulmonary complications were also markedly increased, particularly viral infections (HR 15.8 [10.74, 23.26]) and respiratory failure (HR 11.52 [7.11, 18.66]) (Figure 1). HSCT recipients demonstrated impaired left ventricular myocardial deformation, characterised by reduced global strain, alongside reduced lung volumes (Figure 2). Older age at transplant, allogeneic grafts, male sex, pre-transplant smoking, alcohol use and diabetes were associated with higher cardiopulmonary risk (p < 0.05). Conclusion HSCT survivors experienced a substantially increased risk of long-term cardiovascular and pulmonary morbidity and subclinical organ remodelling. These findings support the need for systematic long-term surveillance strategies, particularly in an ageing transplant-eligible population with increasing comorbidity burden.Figure 1Figure 2