PATHOLOGICAL SEQUELAE OF LONG-TERM HEART ASSIST WITH CONTINUOUS FLOW LEFT VENTRICULAR ASSIST IN CALVES

Abstract

Objectives; The aim of this study is evaluation of thromboembolism and histology of major organs under long-term heart assist with continuous flow left ventricular assist system (LVAS). Methods; Continuous flow LVAS were implanted in 10 calves. There were two groups. Group S: Short-term assist <1 month and group L: Long-term assist >4 months. At the end of each study, histopathology was performed on major organs to evaluate thromboembolism and effects of continuous flow VAD support. Results; Mean assist duration was 17.6(15–21) days in group S (n=3) and 167.3(141–223) days in group L (n=7). There was no difference between these two groups in pump flow rate and pulsatility index ((systolic blood pressure-diastolic blood pressure) /mean blood pressure). With the exception of renal infarcts, no thromboembolism was found in either group. There was no pathological changes in major organs in group S, but all of group L calves had chronic interstitial nephritis and two of them had marked hypertrophy of smooth muscle cell in small renal arteries. Two of group L had myocardial atrophy. Liver, spleen, gastrointestinal tract were all normal in both groups. Conclusion; Our results suggest the possibility of hypertrophy of small arterial structure in long-term assist with continuous flow LVAS. However, since it is not clear whether these changes are primary or compensatory due to atrophy with diminished pulsatility, further research will need to be done.