Smoking after heart transplantation: an underestimated hazard?

Abstract

Risk factors for the development of vasculopathy and malignancies as the most important causes of morbidity and mortality after heart transplantation are not well defined. Univariate and multivariate Cox regression analysis of the data derived from our 84 survivors of more than 3 months after orthotopic heart transplantation between 1984 and 1996. Measurement of carbonmonoxide-hemoglobin blood levels with an ABL 520 analyzer. Recipient or donor age, the mode of immunosuppression, total-, LDL- and HDL-cholesterol, the HDL/LDL-ratio, triglycerides, hypertension, diabetes mellitus, CMV status and rejection episodes had no independent influence on total mortality or the occurrence of graft vasculopathy or cancer. By means of an intensive questionnaire (in case of deceased patients, by their relatives) and measurement of CO-Hb blood levels we detected a high rate of patients who smoked after transplantation (22/84 = 26%). Four patients confessed smoking after undergoing the blood test. Non-smokers were defined as denying it in the questionnaire and having CO-Mb levels < 2.5% in repeated measurements. All but one were smokers before heart transplantation. Mean consumption was 11 cigarettes per day. Five and 10 years survival was significantly reduced in smokers vs. non-smokers (37 vs. 80% and 10 vs. 74%, respectively, P < 0.0001). Survival curves diverged dramatically after 4 years of observation. Smokers had a higher prevalence of transplant vasculopathy as revealed by coronary angiography and/or autopsy (10/22 smokers vs. 2/62 non-smokers, P < 0.00001) and a higher rate of malignancies (7/22 smokers developed cancer, as compared to 4 cancers in 62 non-smokers, P = 0.0001). The primary site of cancer was the lung in 5/6 smoking and lymphoma in all non-smoking cancer patients. Our data show that the prevalence of smoking after heart transplantation may be relatively high, especially in former smokers. Repeated measurements of CO-Hb could be helpful in its detection. Despite a relatively low cigarette count, smoking is a major risk factor of morbidity and mortality after heart transplantation (HTx). Approximately 4 years of exposure time is needed to uncover its negative influence. These findings should lead to aggressive smoking screening and weaning programs in every HTx center.