RT Journal Article
SR Electronic
T1 1 Why is cold air associated with increased susceptibility to myocardial ischaemia?
JF Heart
JO Heart
FD BMJ Publishing Group Ltd and British Cardiovascular Society
SP A1
OP A1
DO 10.1136/heartjnl-2016-309588.1
VO 102
IS Suppl 4
A1 R Williams
A1 K Asrress
A1 G de Waard
A1 M Lumley
A1 S Arri
A1 T Patterson
A1 H Ellis
A1 N Briceno
A1 Z Khawaja
A1 A Chiribiri
A1 B Clapp
A1 S Plein
A1 N Van Royen
A1 D Perera
A1 M Marber
A1 S Redwood
YR 2016
UL http://heart.bmj.com/content/102/Suppl_4/A1.1.abstract
AB Introduction Cold air inhalation (CAI) during exercise increases cardiac mortality. The pathophysiology remains unclear, but may reflect adverse changes in microvascular resistance (MVR). We compared the accuracy of two novel intra-coronary measures of MVR to predict microvascular dysfunction (MVD). We then used the best MVR measure to quantify changes during CAI, exercise alone and exercise with CAI.Methods 56 patients (74 arteries: post PCI or FFR >0.8) had hyperaemic microvascular resistance (hMR) and index of microcirculatory resistance (IMR) compared against:Coronary flow reserve (CFR)CMR perfusionCMR microvascular obstruction (MVO).In a further 55 patients (45 with coronary artery disease (CAD), baseline and peak MVR was measured after 5 min of either:CAI (-15oC)CyclingCAI during cycling.Results hMR had better diagnostic accuracy than IMR to predict CFR (AUC 0.82 vs. 0.58), CMR perfusion (AUC 0.85 vs. 0.72) and MVO (AUC 0.83 vs. 0.72) (Figure 1, Study 1).CAI at rest decreased MVR in patients with normal coronaries but increased MVR in CAD patients (p < 0.01) (Figure 1, Study 2). In CAD patients, cycling caused an adaptive decrease in MVR (p < 0.0001), but CAI during cycling abolished this decrease (Figure 1, Study 2).ConclusionshMR is a better predictor of MVD than IMR.CAI causes adverse changes in MVR in CAD patients both at rest and during exercise, rendering the heart more susceptible to ischaemia.Abstract 1 Figure 1 Investigation of best invasive measure of microvascular resistance (Study 1), and its application during cold air inhalation (CAI) at rest, and during exercise (Study 2)