Abstract
In Parkinson's disease (PD), cardiovascular dysautonomia accumulates with disease progression, but studies are lacking on the natural history behind each subtype except orthostatic hypotension. This study investigated the early natural history of orthostatic blood pressure (BP) subtypes in PD. Two hundred sixty-seven early PD patients were included. Their cardiovascular functions were assessed by head-up tilt-test and (123)I-metaiodobenzylguanidine scintigraphy. All patients were classified as having supine hypertension (SH), orthostatic hypertension (OHT), delayed orthostatic hypotension (dOH), or orthostatic hypotension (OH) according to consensus criteria. The patients were assigned to one of three groups: extreme BP dysregulation (BP(extreme)), mild BP dysregulation (BP(mild)), and no BP dysregulation (BP(none)) according to their orthostatic BP subtypes. The autonomic functions of 237 patients were re-assessed after approximately 3 years. Among initially enrolled subjects, 61.8% of the patients showed orthostatic BP dysregulation: 29.6% in the BP(extreme) group and 32.2% in the BP(mild) group. At follow-up, the BP(extreme) group increased in number, while the BP(mild) group diminished. Two-thirds of the initial BP(extreme) patients maintained their initial subtype at follow-up. In comparison, 40.7% of the initial BP(mild) patients progressed to the BP(extreme) group, and 32.4% and 14.7% of the initial BP(none) group progressed to BP(extreme) and BP(mild) groups, respectively. Cardiac denervation was most severe in the BP(extreme) group, and a linear gradient of impairment was observed across the subtypes. In conclusion, various forms of positional BP dysregulation were observed during the early disease stage. SH and OH increased with disease progression, while OHT and dOH decreased, converting primarily to SH and/or OH.