Pulsatility and flow patterns across macro- and microcirculatory arteries of continuous-flow left ventricular assist device patients.

BACKGROUND: Reduced arterial pulsatility in continuous-flow left ventricular assist devices (CF-LVAD) patients has been implicated in clinical complications. Consequently, recent improvements in clinical outcomes have been attributed to the "artificial pulse" technology inherent to the HeartMate3 (HM3) LVAD. However, the effect of the "artificial pulse" on arterial flow, transmission of pulsatility into the microcirculation and its association with LVAD pump parameters is not known. METHODS: The local flow oscillation (pulsatility index, PI) of common carotid arteries (CCAs), middle cerebral arteries (MCAs) and central retinal arteries (CRAs-representing the microcirculation) were quantified by 2D-aligned, angle-corrected Doppler ultrasound in 148 participants: healthy controls, n = 32; heart failure (HF), n = 43; HeartMate II (HMII), n = 32; HM3, n = 41. RESULTS: In HM3 patients, 2D-Doppler PI in beats with "artificial pulse" and beats with "continuous-flow" was similar to that of HMII patients across the macro- and microcirculation. Additionally, peak systolic velocity did not differ between HM3 and HMII patients. Transmission of PI into the microcirculation was higher in both HM3 (during the beats with "artificial pulse") and in HMII patients compared with HF patients. LVAD pump speed was inversely associated with microvascular PI in HMII and HM3 (HMII, r2 = 0.51, p < 0.0001; HM3 "continuous-flow," r2 = 0.32, p = 0.0009; HM3 "artificial pulse," r2 = 0.23, p = 0.007), while LVAD pump PI was only associated with microcirculatory PI in HMII patients. CONCLUSIONS: The "artificial pulse" of the HM3 is detectable in the macro- and microcirculation but without creating a significant alteration in PI compared with HMII patients. Increased transmission of pulsatility and the association between pump speed and PI in the microcirculation indicate that the future clinical care of HM3 patients may involve individualized pump settings according to the microcirculatory PI in specific end-organs.

Carotid artery distensibility: a reliability study.

OBJECTIVE: Carotid distensibility (CD) is a measure of carotid artery elasticity that has been introduced as a risk factor for cardiovascular disease. Information regarding reproducibility of sonographic CD measures is limited. The objective of this study was to evaluate the inter-reader reliability of sonographic measurements of common carotid artery (CCA) diameters and derived metrics of CD. METHODS: Two independent readers (R1 and R2) measured the systolic diameter (SD) and diastolic diameter (DD) for the right CCA from the B/M-mode sonographic registrations among 118 subjects. The derived CD metrics (strain, elastic modulus [E], stiffness [beta], and CD) were calculated. The inter-reader type 3 intraclass correlation coefficients (ICC3,1) for carotid diameters were calculated. RESULTS: The mean SDs +/- standard deviation were 7.15 +/- 1.43 mm for R1 and 7.24 +/- 1.43 mm for R2. The mean DDs were 6.71 +/- 1.36 mm for R1 and 6.68 +/- 1.41 mm for R2. The mean differences of SD and DD between R1 and R2 were 0.08 +/- 0.40 mm (paired t test, P = .04) and 0.03 +/- 0.43 mm (paired t test, P = .46), respectively. Inter-reader type 3 intraclass correlation coefficients were 0.96 for SD and 0.95 for DD. We observed a significant association of demographics with carotid diameters but not with derived CD metrics or risk factors. CONCLUSIONS: Our results suggest good reproducibility of CCA diameters measured with B/M-mode sonography. However, very small changes in linear measurements of carotid diameters can have big effects on estimates of arterial mechanical properties such as strain and Young's modulus. The standard boundary identification methods may not be precise and reproducible enough for use in a clinical setting.

Analysis of risk factors for perforated duodenal ulcer: A retrospective study

This retrospective study included all patients operated on for perforated duodenal ulcer at Vicente Sotto Memorial Medical Center, Department of General Surgery from January 1994 to March 1997. It was conducted to identify the factors that would significantly affect the morbidity and mortality among patients undergoing surgery for perforated duodenal ulcer, and to demonstrate the value of a risk grading system in determining the associated mortality rate of a certain risk score. Concurrent serious medical illness, preoperative hypotension (BP100mm Hg), and perforation more than 48 hours were the significant clinical parameters that increased the mortality rate. Among patients treated by definitive surgery, 89.1 per cent were free of any risk factor compared to only 40.4 per cent for patients operated by simple closure. There was a significant relationship (p0.0001) between the risk score and the mortality rate. The mortality rate increased progressively with increased risk score: 0.0 per cent with no risk factor present, 9.1 per cent with one risk factor, 38.5 per cent with two risk factors, and 100 per cent with three risk factors. These finding underscored the importance of patient selection and the feasibility of a risk grading system in guiding surgical management. (Author)