This Article Abstract Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Marzilli, M. Articles by L’Abbate, A. Search for Related Content PubMed PubMed Citation Articles by Marzilli, M. Articles by L’Abbate, A.

Coronary microcirculatory vasoconstriction during ischemia in patients with unstable angina

^a CNR Institute of Clinical Physiology, Pisa, Italy

View larger version (21K): [in a new window]   Figure 1 Behavior of heart rate (top), systolic and diastolic arterial pressure (bottom) at baseline, during adenosine (ADN) in the first 30 s following the appearance of ST segment shift (early ischemia) at maximum ST displacement (max ischemia), early after intracoronary administration of nitrates (early rec), at restoration of baseline hemodynamics (full rec) and during balloon coronary occlusion. Circles connected by the thicker line represent average, vertical linesshow SDs. Heart rate and arterial pressure remained relatively stable throughout the study.

View larger version (24K): [in a new window]   Figure 2 Transstenotic pressure gradient (top), distal coronary pressure (middle) and percent blood flow velocity (bottom) values at the various steps of the protocol as indicated in Figure 1. Blood flow velocity was assumed to be zero during balloon coronary occlusion (dashed line). Despite very different flow values, distal coronary pressure was similar following adenosine and during maximal ST shift; by contrast, it was markedly lower during balloon coronary occlusion (* = p < 0.05 vs. baseline; = p < 0.05 vs. adenosine; = p < 0.05 vs. max ischemia).

View larger version (57K): [in a new window]   Figure 3 Coronary angiography, ECG (D3), aortic and distal coronary pressure and coronary blood flow velocity (CBFV) in a patients with stenosis and transient occlusion of the left circumflex coronary artery. Adenosine increased transstenotic pressure gradient and blood flow. During ischemia and ST segment elevation in D3, distal coronary pressure was similar to that observed following adenosine. During balloon occlusion (PTCA) distal pressure was markedly lower, while blood flow velocity was not monitored.

View larger version (60K): [in a new window]   Figure 4 Coronary angiography, electrocardiogram (D3, V4), aortic and distal coronary pressure and coronary blood flow velocity (CBFV) in patients with stenosis and transient occlusion of the left anterior descending coronary artery. Adenosine increased transstenotic pressure gradient and blood flow. During ischemia and ST segment elevation in V4, distal coronary pressure was similar to that observed following adenosine. During balloon occlusion (PTCA) distal pressure was markedly lower, while blood flow velocity was not monitored.

View larger version (20K): [in a new window]   Figure 5 Coronary resistance at the level of epicardial stenosis (top) and in distal microcirculation (middle) at the various steps of the protocol as indicated in Figure 1. Bottom panel shows the behavior of total coronary resistance and the contribution of stenosis (black) and microvascular resistance (white columns). Coronary resistance was not calculated during balloon coronary occlusion. During ischemia, both coronary stenosis and distal microcirculation showed a significant increase in resistance to flow (* = p < 0.05 vs. baseline, = p < 0.05 vs. adenosine; = p < 0.05 vs. max ischemia).