Assessment of the structural and functional state of blood vessels in patients with hypertrophic cardiomyopathy

Abstract

Aim To evaluate the structural and functional condition of the vasculature using fingertip photoplethysmography and computerized videocapillaroscopy in patients with hypertrophic cardiomyopathy (HCMP).Material and methods The study included patients with HCMP (n=48; 28 (57 %) men; age, 54.3±13.6 years) and healthy volunteers (control group, n=33, 15 (45 %) men; age, 58.2±8.8 years). Standard laboratory and instrumental examination (blood count and biochemistry, electrocardiography, echocardiography, Holter electrocardiogram monitoring) were performed for all HCMP patients. The condition of vascular wall at various levels of the vasculature was evaluated by fingertip photoplethysmography (apparatus Angioscan-01) and computerized nail-fold videocapillaroscopy (apparatus Capillaroscan-01). The photoplethysmography study analyzed structural parameters, including the arterial wall stiffness index (aSI) of large blood vessels and the resistance index (RI) of small muscular arteries. Endothelial dysfunction was evaluated by the occlusion index (OI) and phase shift (PS). The capillaroscopy study assessed structural parameters, including the resting capillary density (rCD) and the capillary density following venous occlusion (voCD), and functional parameters, including the percentage of perfused capillaries (PPC), the percentage of restored capillaries (PRC), and the capillary density after the reactive hyperemia test (rhCD).Results The study showed increases in aSI (8.8 [6.8; 12.2] and RI (32.5 [17.4; 47.9] in the HCMP group. The OI was significantly lower in the HCMP group (1.3 [1.1; 1.5]) than in the control group (1.8 [1.5; 2.7], р<0.001). Also, PS values were significantly decreased in the HCMP group (4.4 [2.3; 8.6]) compared to the control group (8.4 [5.1; 12.1]. p=0.018). Disorders of structural and functional capillary indexes were observed in HCMP patients compared to the control group; rCD and voCD were decreased in the HCMP group (60 [52.6; 68] and 88 [75; 90], respectively) compared to the control group (75.8 [60; 87] and 90 [73; 101]), however, no intergroup difference reached a statistical significance. The rhCD, PPC, and PRC values were decreased in the HCMP group (66.3 [55; 72], 86.7 [70.9; 104.2] and 1.7 [–6.95; 20.3], respectively) compared to the control group (86 [68.6; 100], 103 [96; 114] and 18.4 [8.1; 27.4], respectively); PPC and PRC values were significantly different (р<0.005 and p<0.004, respectively).Conclusion In patients with HCMP, fingertip photoplethysmography and computerized videocapillaroscopy showed increased wall stiffness in both large blood vessels and microvasculature, pronounced endothelial dysfunction, and decreases in capillary density and percentage of restored capillaries following respective tests.

Mechanisms and prognostic impact of myocardial ischaemia in hypertrophic cardiomyopathy

“…As many as 56–83% of HCM patients have small vessel disease to some degree [ 49 – 52 ]. The abnormalities typically include marked thickening of the vessel walls, luminal narrowing of small intramural coronary arteries [ 53 ] and increased arterial stiffness [ 54 ]. The luminal area of arterioles, as a percentage of total vascular area, has been measured to be 13–30% lower in HCM patients than in controls [ 55 – 57 ], with 14% of small vessels in one study having an external diameter:lumen ratio ≥ 3 (normally < 2.5) [ 58 ].…”

“…Numerous studies have measured the density of small vessels in hypertrophied HCM septal/LV tissue samples and have found this to be 21–44% lower than in control patients [ 54 , 56 , 57 , 60 – 63 ]. With no convincing association with genotype [ 61 ], reductions in small vessel density may be linked to hypertrophy in HCM and are more severe in end-stage disease patients, such as those undergoing heart transplantation, than in patients referred for myectomy [ 62 ].…”