Patients with severe aortic stenosis had significantly higher absolute resting coronary flow compared to matched controls, resulting in impaired coronary flow reserve (2.30 vs 2.89, p=0.005).
Observational (n=44)
Does severe aortic stenosis alter absolute coronary flow, microvascular resistance, CFR, and MRR compared to matched controls?
In patients with severe aortic stenosis, increased resting coronary flow compensates for left ventricular hypertrophy but leads to significantly impaired coronary flow reserve and microvascular resistance reserve.
Absolute Event Rate: 2.3% vs 2.89%
p-value: p=0.005
Abstract Introduction The development of left ventricular hypertrophy in patients with severe aortic stenosis (AS) is accompanied by adaptive coronary flow regulation, both in epicardial and microvascular compartment, which ultimately lead to a chronic ischemic insult even in the absence of obstructive coronary artery disease. Intracoronary continuous thermodilution of saline through a dedicated infusion catheter is a novel tool that allows to measure absolute coronary flow and microvascular resistance at rest and during hyperemia and to calculate both coronary flow reserve (CFR) and Microvascular Resistance Reserve (MRR) Purpose We aimed to assess absolute coronary flow, microvascular resistance, CFR and MRR in patients with AS, by continuous intracoronary thermodilution, comparing these hemodynamic findings with a propensity-score matched contemporary cohort of patients without AS. Methods Absolute coronary blood flow and microvascular resistance were measured by continuous thermodilution in 29 patients with AS and compared to 15 controls matched for age, gender, diabetes mellitus and functional severity of epicardial coronary lesions. Myocardial work, total myocardial mass and LAD-specific mass were quantified by echocardiography and cardiac-CT. Results Patients with AS presented a significantly positive LV remodeling with lower global longitudinal strain and higher global work index compared to controls (p0.02). Total LV myocardial mass and LAD-specific myocardial mass were significantly higher in patients with AS. Compared to matched controls, absolute resting flow in the LAD was significantly higher in the AS cohort (86 66–107 ml/min vs 68 52–75 ml/min, p=0.036), resulting, in lower CFR (2.30±0.69 vs 2.89±0.77, p=0.005) and MRR (2.73±0.74 vs 3.53±0.95, p=0.005) in the AS cohort compared to controls (Figure 1). No differences were found in hyperemic flow and resting and hyperemic resistances. Interestingly, hyperemic myocardial perfusion (calculated as the ratio between the absolute coronary flow in the LAD and the mass subtended by the vessel, expressed in mL/min/g), but not resting, was significantly lower in the AS group (1.9 1.5–2.5 ml/min/g vs 2.3 2–3.1 ml/min/g p=0.036). Conclusions In patients with severe aortic stenosis and non-obstructive coronary artery disease, with the progression of LVH, the compensatory mechanism of increased resting flow maintains an adequate perfusion at rest, but not during hyperemia (Figure 2). As consequence, both CFR and MRR are significantly impaired. Funding Acknowledgement Type of funding sources: None.
Gallinoro et al. (Sat,) conducted a observational in Severe aortic stenosis (n=44). Continuous intracoronary thermodilution vs. Propensity-score matched controls without aortic stenosis was evaluated on Coronary flow reserve (CFR) (p=0.005). Patients with severe aortic stenosis had significantly higher absolute resting coronary flow compared to matched controls, resulting in impaired coronary flow reserve (2.30 vs 2.89, p=0.005).