Changes in diastolic regional stiffness of the left ventricle before and after coronary artery bypass grafting

Abstract

To evaluate the effect of coronary artery bypass grafting (CABG) on regional diastolic function of the left ventricular wall, we applied the concept of the stiffness constant to the diastolic sigma-ln (1/H) relation, where sigma is the mean wall stress, and H is the wall thickness of the region of concern, and ln (1/H) is the natural logarithm of the reciprocal of wall thickness. We assessed 12 cardiac regions in six patients with coronary artery disease who underwent CABG at the Cardiovascular Hospital of Central Japan between May 1994 and January 1995. Left ventricular pressure and regional wall thickness were measured simultaneously, with a micromanometer-tipped catheter and by two-dimensional echocardiography, respectively, before and after CABG. The stiffness constant (K) was obtained by fitting the diastolic sigma-ln (1/H) data points to an exponential curve with zero asymptote: sigma = Cexp[Kln (1/H)]. Preoperatively, the stiffness constant in the affected region (CABG region) was greater than that in the unaffected region (non-CABG region) (4.79 +/- 2.56 vs 2.95 +/- 0.72). Postoperatively, the stiffness constant in the CABG region was significantly decreased, to 3.21 +/- 1.22. The stiffness constant, which is derived from the sigma-ln (1/H) relation, is useful for the assessment of LV regional diastolic function.

Nicorandil Infusion Leads to Good Recovery From Ischemia of Left Ventricular Regional Work in Comparison With Nitroglycerin.

“…21 In the present study, however, we did not evaluate collateral circulation during balloon inflation to the LAD. There may have been some prior differences in collateral circulation between the 2 groups according to the degree of prodromal myocardial ischemia.…”

“…[19][20][21][22][23] We used their concept to assess changes in left ventricular (LV) RW during PTCA, and compared the effects of NR and nitroglycerin (NG) on the recovery of RW from ischemia.…”

Electrocardiographic ST-Segment Elevation and Changes in the Regional Work of the Left Ventricle During Coronary Angioplasty

“…The stress ( ) was defined as PD/4H, and the strain was defined as ln (1/H) (the natural logarithm of the reciprocal of wall thickness), which is equivalent to area strain of the midwall layer. [1][2][3][4][5][6][7][8][9] …”

“…In the present study, we used the concept of regional work derived from the relation between mean wall stress and strain (the natural logarithm of the reciprocal of wall thickness) proposed by Sugawara et al [1][2][3][4][5][6][7][8][9] The value of the regional work is normalized to unit volume of myocardium; therefore, the results obtained from hearts of differing size and wall thickness can be compared.…”

“…Therefore, PTCA is useful for studying the effects of acute regional myocardial ischemia on left ventricular (LV) function.Regional myocardial work is used to analyze regional dysfunction of the LV in patients with coronary artery disease (CAD), [1][2][3][4] and in the present study we used the method proposed by Nakano and Sugawara et al, [1][2][3][4][5][6][7][8][9] which is based on the simultaneous measurement of LV pressure and LV regional wall thickness to give regional work normalized to unit volume of myocardium in true unit of work (mJ/cm 3 ).The purpose of this study was to assess the change in regional work of the LV wall and correlate it with STsegment elevation during PTCA to the proximal left anterior descending artery (LAD). …”