Acute myocardial infarction in a patient with HAM/TSP evaluated for circulatory dynamics during mobilization before and after antihypertensive drug modification: a case report

BACKGROUND: Antihypertensive therapy plays a crucial role in managing cardiovascular disease but may sometimes cause significant hypotension during mobilization, hindering the recovery of activities of daily living. In patients struggling with orthostatic hypotension, evaluating circulatory dynamics using a tilt bed provides rich clinical insights for identifying the underlying pathophysiology. We encountered a rare case in which the patient also had HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), prompting an assessment of circulatory dynamics in the passive upright posture. We also aim to suggest that evaluating blood pressure responses using a tilt bed may provide valuable insights when antihypertensive management inadvertently limits functional improvement. CASE PRESENTATION: A 74-year-old Japanese man with diabetes, chronic kidney disease, and slowly progressive HAM/TSP was admitted with acute myocardial infarction. Despite successful percutaneous coronary intervention, early mobilization was repeatedly interrupted by significant drops in blood pressure, leading to episodes of decreased consciousness. While resting blood pressure remained stable, passive upright posture with a tilt bed revealed that before modifying his antihypertensive regimen, his systolic blood pressure initially dropped by approximately 15 mmHg immediately after tilting and continued to decline for up to 10 min, ultimately reaching a total decrease of approximately 20 mmHg from baseline. After switching from sacubitril/valsartan to enalapril, an initial drop of 10-15 mmHg was still observed in the passive upright posture; however, blood pressure soon began to recover, preventing sustained hypotension. Consequently, the patient no longer experienced pronounced hypotension upon standing, enabling a more intensive rehabilitation program that ultimately led to improved activities of daily living. CONCLUSIONS: Our findings highlight that evaluating circulatory dynamics using a tilt bed provides critical clinical insights for optimizing medication and rehabilitation in patients whose recovery is impeded by orthostatic hypotension. Furthermore, it is essential to recognize that circulatory dynamics during mobilization can change significantly following medication adjustments. This approach may facilitate early mobilization and help mitigate prolonged hypotension that limits functional gains in selected patients.