Cyclic Variation of Myocardial Integrated Backscatter and Myocardial Wall Thickness During Percutaneous Coronary Angioplasty

Cyclic variation of myocardial integrated backscatter (CVIBS) and change in myocardial wall thickness (WT%) were evaluated during percutaneous transluminal coronary angioplasty (PTCA). Fourteen patients who underwent PTCA of the proximal left anterior descending (LAD) coronary artery were included in the study. PTCA was performed by inflating the balloon at the site of the LAD lesion for 1 minute. CVIBS was measured at three episodes during PTCA in the parasternal short‐axis view: before the inflation, at the end of 1‐minute inflation, and at the fifth‐minute after deflation of the balloon. Three regions of interest were used to evaluate the three‐vessel territories: mid‐anteroseptal area for LAD, mid‐posterolateral area for circumflex artery, and mid‐inferior area for right coronary artery. The WT% was calculated in each area. In the LAD territory, CVIBS measured at the end of 1‐minute inflation was lower than the values obtained before PTCA, 5.2 ± 1.0 decibel (dB) versus 3.7 ± 0.7 dB (P < 0.01) . CVIBS magnitudes increased at the fifth‐minute after the deflation back up even to higher levels than pre‐PTCA values, 6.1 ± 1.0 dB versus 5.2 ± 1.0 dB (P < 0.01) . The WT% values decreased during balloon inflation but did not recover to the pre‐inflation values measured at fifth‐minute after deflation. In other sites, there was no change in either CVIBS or WT% values at any time studied. The observed increase in CVIBS may be an indicator of restoration of blood flow to ischemic myocardium. (ECHOCARDIOGRAPHY, Volume 20, July 2003)