Reverse remodeling after endoventricular circular patch plasty in the mid-term period
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《血管的通路杂志》
Department of Cardiovascular Surgery, Fukui CardioVascular Center, Shinbo 2-228, Fukui, 910-0833 Japan
Abstract
It has been reported that surgical repair of anterior left ventricular (LV) aneurysms is associated with reverse remodeling and improved myocardial function in the inferior LV wall. We evaluated wall motion in RCA territory using QGS in the mid-term period after endoventricular circular patch plasty (EVCPP). Eighteen patients, who underwent EVCPP, were studied by QGS before, and in the early and mid-term periods after surgery. Ten patients underwent CABG to the RCA because of RCA lesions (group B) and the other 8 patients did not have CABG to the RCA (group N). Regional wall thickening function was evaluated by the change in wall thickness through end-systole and end-diastole. We evaluated the RCA territory remote from the incision line of the EVCPP. Regional wall thickness improved significantly in the mid-term period after EVCPP in both groups. Although preoperative wall thickness was worse in group B than in group N, postoperative wall motion in group B was improved as well as in group N in the mid-term period. Inferior LV wall motion improved in patients with and without CABG in the mid-term period. We conclude that reverse remodeling occurred in the mid-term period after EVCPP.
Key Words: Congestive heart failure; Coronary disease; Myocardial infarction
1. Introduction
Mackay et al. proved the decrease in myocardial contractility in the non-infarcted area and proposed the process of left ventricular (LV) remodeling [1]. It was reported that a large and transmural myocardial infarction causes alterations in the topography of the infarcted and noninfarcted regions of the ventricle, and that this remodeling affects the function of the ventricle and the prognosis for survival [2]. Local wall stress is abnormally elevated and might be responsible for the altered kinetics of normally perfused myocardium at the interface of ischemic and nonischemic regions [3]. Surgical treatment for postinfarction LV aneurysm is performed widely. Interestingly, it was reported that surgical treatment for anterior LV aneurysm is associated with reverse remodeling and improved myocardial function in the inferior wall [4,5].
There is a good correlation between quantitative gated single photon emission tomography (QGS) and left ventriculography (LVG) or magnetic resonance imaging (MRI) with respect to assessing LV function [6,7]. We used the QGS method to evaluate regional wall function in the early and the mid-term period after endoventricular circular patch plasty (EVCPP).
2. Materials and methods
2.1. Patients
Between April 1994 and April 2004, 31 patients underwent the EVCPP to repair an anterior left ventricular aneurysm. Eighteen patients were studied by QGS before, and in the early and mid-term periods after surgery. All patients were judged as clinically having heart failure with LV dyskinesia or akinesia. The hospital courses of the patients were uneventful. All 18 patients had concomitant coronary artery bypass grafting (CABG). We assigned the 18 patients to two groups based on whether they had CABG to the right coronary artery (RCA) (Table 1). Ten patients (male) had CABG to the RCA because of RCA lesions (group B). The mean age in group B was 74±5 years and the mean number of bypass grafts was 3.2±0.4 per patient. The remaining 8 patients (5 male and 3 female) did not have CABG to the RCA because of the absence of occlusive lesions in the RCA (group N). However, one patient in group N had small RCA, there was dominancy of RCA in other patients. The patient age in group N was 62±8 years, and the mean number of bypass grafts was 2.1±0.6 per patient. There were statistically significant differences between group B and group N with respect to age and number of bypass grafts. The end-diastolic volume index (EDVI) calculated by QGS in group B was greater than that in group N at all time points.
2.2. Operative procedure
Cardiopulmonary bypass was used in all cases, and 16 patients underwent cardiac arrest using cold blood cardioplegia. The LV incision and reconstruction were performed under ventricular fibrillation in 16 cases, and in the heart-beating state in two cases. For EVCPP, a patch of dacron or bovine pericardium was attached to the border zone between the normal and scarred tissue eventually after a circular purse-string suture was passed to restore a new apical neck. The aneurysmal sac was closed over the patch with two strips of felt for reinforcement.
Revascularization was performed in all patients by CABG. The left internal mammary artery was implanted in the left anterior descending artery in 15 patients and in the diagonal branch or the circumflex coronary artery in 3 patients.
2.3. Radionuclide study
One hour after injection of 740 MBq 99mTc-tetrofosmin, QGS rest images were obtained. The data were analyzed with the QGS(+) program produced by Germano and co-workers. The wall thickness between the epicardial and endocardial surfaces was determined, and wall thickness change was computed between end-diastole and end-systole and is expressed as the percent increase from diastolic thickness [8]. Polar maps divided into 20 segments were generated by the QGS(+) program as shown in Fig. 1 and quantitative values were calculated. Regional wall thickening function was evaluated by the change in regional wall thickness through systole and diastole objectively and automatically. We evaluated segments 7, 8, 10, and 11 in Fig. 1 as the RCA territory remote from the incision line of EVCPP. QGS study was performed before surgery, early postoperatively (group B: 44±47, group N: 22±7 days after surgery) and mid-term postoperatively (group B: 38±7, group N: 27±12 months after surgery).
2.4. Statistical analysis
All results were reported as mean±standard deviation. The paired t-test was used for comparisons between preoperative and early-postoperative values, and between early and mid-term postoperative values. The unpaired t-test was used for the comparison of values between group B and group N. A P-value of less than 0.05 was considered statistically significant.
3. Results
3.1. Comparsion in wall thickening
3.1.1. Segment 7 (Table 2)
There was no significant difference between preoperative values and early postoperative values, and between early and mid-term postoperative values in either group. Furthermore, there was no significant difference between group B and group N at any time point.
3.1.2. Segment 8 (Table 3)
No significant difference between preoperative and early postoperative values was seen in both groups. However, significant differences were observed between the early and mid-term postoperative values in both groups. Although there was a significant difference between group B and group N preoperatively, there was no significant difference between group B and group N in the early and mid-term postoperative periods.
3.1.3. Segment 10 (Table 4)
Although a significant difference between the preoperative value and early postoperative value was seen in group B, no significant difference between the early and mid-term postoperative values was seen in the same group. In group N, there was no significant difference between the preoperatively and early postoperatively, but there was a significant difference between the early and mid-term postoperatively. Though no significant difference between group B and group N was seen preoperatively and early postoperatively, a significant difference between group B and group N was found in the mid-term postoperative period.
3.1.4. Segment 11 (Table 5)
There was no significant difference between the preoperative and early postoperative values in group B, but there was a significant difference between the early and mid-term postoperative values. Also in group N, there was no significant difference between preoperatively and early postoperatively, but there was a significant difference between the early and mid-term postoperatively. As in segment 8, there was a significant difference between group B and group N preoperatively, but there were no significant early postoperative and mid-term postoperative differences.
4. Discussion
Kramer and co-workers suggested that the mechanical effects of the aneurysm on noninfarcted regions is caused by elevated local wall stress in an ovine model of LV anteroapical aneurysm and that intramyocardial function remained depressed in noninfarcted regions adjacent to the aneurysm [9]. An increase in compliance leads to increased wall stress and decreased global mechanical performance [5]. However, LV aneurysm resection leads to improvement in remote regional performance due to reductions in local wall stress in the remote regions [4,5]. Our study revealed that wall function improved significantly in the mid-term period after surgery in patients without RCA territory disease. This result indicates that EVCPP improves remote regional function as reported by Di Donato [4] and Kramer [5].
Furthermore, the present study revealed that the percent increase in wall thickness in group B was worse than that in group N, but that the percent increase in group B improved, as in group N, after surgery. Since oxygen consumption is directly related to myocardial stress [10], oxygen demand in the remote noninfarcted muscle in- creases. Moreover, the existence of coronary artery lesions decreases oxygen supply. We believe that the supply imbalance resulted in a lower percent increase in wall thickness in group B. The marked decrease in left ventricular volume reduces not only wall tension but also oxygen demand [11]. We believe that the reduction in wall tension and oxygen demand by EVCPP and the increase of oxygen supply by CABG produced dramatic improvements in the percent increase in wall thickness in group B. These results indicate that revascularization to the RCA is very important [12].
Kramer and co-authors demonstrated that the improvement of LV function after LV aneurysm repair is most marked in the middle of the left ventricle and the base and inferior wall remote from the aneurysm [5]. Di Donato and co-workers reported that postoperative functional improvement is mainly related to the increase in inferior LV wall motion [12]. Our present study also shows that wall thickening in the basal inferior and/or posterior wall improves in the mid-term period after EVCPP. Our previous study demonstrated that the improvement of LV systolic function is maintained not only in the early period but also in the mid-term period after EVCPP [13]. We believe that the improvement in LV function after EVCPP is caused by a marked reduction in volume and increased inferior LV wall motion in the early period after EVCPP. We believe that the process of reverse remodeling continues in the mid-term period.
References
McKay RG, Pfeffer MA, Pasternak RC, Markis JE, Come PC, Nakao S, Alderman JD, Ferguson JJ, Safian RD, Grossman W. Left ventricular remodeling after myocardial infarction: a corollary to infarct expansion. Circulation 1986;74:693–702.
Pfeffer MA, Braunwald E. Ventricular remodeling after myocardial infarction. Circulation 1990;81:1161–1172.
Bogen DK, Rabinowitz SA, Needleman A, McMahon TA, Abelmann WH. An analysis of the mechanical disadvantage of myocardial infarction in the canine left ventricle. Circ Res 1980;47:728–741.
Di Donato M, Sabatier M, Toso A, Barletta G, Baroni M, Dor V, Fantini F. Regional myocardial performance of non-ischaemic zones remote from anterior wall left ventricular aneurysm. Effect of aneurysmectomy. Eur Heart J 1995;16:1285–1292.
Kramer CM, Magovern JA, Rogers WJ, Vido D, Savage EB. Reverse remodeling and improved regional function after repair of left ventricular aneurysm. J Thorac Cardiovasc Surg 2002;123:700–706.
Yoshioka J, Hasegawa S, Yamaguchi H, Tokita N, Paul AK, Xiuli M, Maruyama A, Hori M, Nishimura T. Left ventricular volumes and ejection fraction calculated from quantitative elactrocardiographic-gated 99mTC-tetrofosmin myocardial SPECT. J Nucl Med 1999;40:1693–1698.
Kondo C, Fukushima K, Kusakabe K. Measurement of left ventricular volumes and ejection fraction by quantitative gated SPET, contrast ventriculography and magnetic resonance imaging: a meta-analysis. Eur J Nucl Med Mol Imaging 2003;30:851–858.
Germano G, Erel J, Lewin H, Kavanagh PB, Berman DS. Automatic quantitation of regional myocardial wall motion and thickening from gated technetium-99 m sestamibi myocardial perfusion single-photon emission computed tomography. J Am Coll Cardiol 1997;30:1360–1367.
Kramer CM, Lima JAC, Reichek N, Frrari VA, Llaneras MR, Palmon LC, Yah IT, Tallant B, Axel L. Reginal function within non-infarcted myocardium during left ventricular remodeling. Circulation 1993;88:1279–1288.
Maroko PR, Braunwald PR. Modification of myocardial infarction size after coronary occlusion. Ann Int Med 1973;79:720–733.
Di Donato M, Sabatier M, Dor V, Toso A, Maioli M, Fantini F. Akinetic vs. dyskinetic postinfarction scar: relation to surgical outcome in patients undergoing endoventricular circular patch plasty repair. J Am Coll Cardiol 1997;29:1569–1575.
Di Donato M, Barletta G, Maioli M, Fantini F, Coste P, Sabatier M, Montiglio F, Dor V. Early hemodynamic results of left ventricular reconstructive surgery for anterior wall left ventricular aneurysm. Am J Cardiol 1992;69:886–890.
Fujii H, Ohashi H, Tsutsumi Y, Kawai T, Iino K, Onaka M. Radionuclide study of mid-term left ventricular function after endoventricular circular patch plasty. Eur J Cardio-thorac Surg 2004;26:125–128.(Hiromichi Fujii, Hirokazu)
Abstract
It has been reported that surgical repair of anterior left ventricular (LV) aneurysms is associated with reverse remodeling and improved myocardial function in the inferior LV wall. We evaluated wall motion in RCA territory using QGS in the mid-term period after endoventricular circular patch plasty (EVCPP). Eighteen patients, who underwent EVCPP, were studied by QGS before, and in the early and mid-term periods after surgery. Ten patients underwent CABG to the RCA because of RCA lesions (group B) and the other 8 patients did not have CABG to the RCA (group N). Regional wall thickening function was evaluated by the change in wall thickness through end-systole and end-diastole. We evaluated the RCA territory remote from the incision line of the EVCPP. Regional wall thickness improved significantly in the mid-term period after EVCPP in both groups. Although preoperative wall thickness was worse in group B than in group N, postoperative wall motion in group B was improved as well as in group N in the mid-term period. Inferior LV wall motion improved in patients with and without CABG in the mid-term period. We conclude that reverse remodeling occurred in the mid-term period after EVCPP.
Key Words: Congestive heart failure; Coronary disease; Myocardial infarction
1. Introduction
Mackay et al. proved the decrease in myocardial contractility in the non-infarcted area and proposed the process of left ventricular (LV) remodeling [1]. It was reported that a large and transmural myocardial infarction causes alterations in the topography of the infarcted and noninfarcted regions of the ventricle, and that this remodeling affects the function of the ventricle and the prognosis for survival [2]. Local wall stress is abnormally elevated and might be responsible for the altered kinetics of normally perfused myocardium at the interface of ischemic and nonischemic regions [3]. Surgical treatment for postinfarction LV aneurysm is performed widely. Interestingly, it was reported that surgical treatment for anterior LV aneurysm is associated with reverse remodeling and improved myocardial function in the inferior wall [4,5].
There is a good correlation between quantitative gated single photon emission tomography (QGS) and left ventriculography (LVG) or magnetic resonance imaging (MRI) with respect to assessing LV function [6,7]. We used the QGS method to evaluate regional wall function in the early and the mid-term period after endoventricular circular patch plasty (EVCPP).
2. Materials and methods
2.1. Patients
Between April 1994 and April 2004, 31 patients underwent the EVCPP to repair an anterior left ventricular aneurysm. Eighteen patients were studied by QGS before, and in the early and mid-term periods after surgery. All patients were judged as clinically having heart failure with LV dyskinesia or akinesia. The hospital courses of the patients were uneventful. All 18 patients had concomitant coronary artery bypass grafting (CABG). We assigned the 18 patients to two groups based on whether they had CABG to the right coronary artery (RCA) (Table 1). Ten patients (male) had CABG to the RCA because of RCA lesions (group B). The mean age in group B was 74±5 years and the mean number of bypass grafts was 3.2±0.4 per patient. The remaining 8 patients (5 male and 3 female) did not have CABG to the RCA because of the absence of occlusive lesions in the RCA (group N). However, one patient in group N had small RCA, there was dominancy of RCA in other patients. The patient age in group N was 62±8 years, and the mean number of bypass grafts was 2.1±0.6 per patient. There were statistically significant differences between group B and group N with respect to age and number of bypass grafts. The end-diastolic volume index (EDVI) calculated by QGS in group B was greater than that in group N at all time points.
2.2. Operative procedure
Cardiopulmonary bypass was used in all cases, and 16 patients underwent cardiac arrest using cold blood cardioplegia. The LV incision and reconstruction were performed under ventricular fibrillation in 16 cases, and in the heart-beating state in two cases. For EVCPP, a patch of dacron or bovine pericardium was attached to the border zone between the normal and scarred tissue eventually after a circular purse-string suture was passed to restore a new apical neck. The aneurysmal sac was closed over the patch with two strips of felt for reinforcement.
Revascularization was performed in all patients by CABG. The left internal mammary artery was implanted in the left anterior descending artery in 15 patients and in the diagonal branch or the circumflex coronary artery in 3 patients.
2.3. Radionuclide study
One hour after injection of 740 MBq 99mTc-tetrofosmin, QGS rest images were obtained. The data were analyzed with the QGS(+) program produced by Germano and co-workers. The wall thickness between the epicardial and endocardial surfaces was determined, and wall thickness change was computed between end-diastole and end-systole and is expressed as the percent increase from diastolic thickness [8]. Polar maps divided into 20 segments were generated by the QGS(+) program as shown in Fig. 1 and quantitative values were calculated. Regional wall thickening function was evaluated by the change in regional wall thickness through systole and diastole objectively and automatically. We evaluated segments 7, 8, 10, and 11 in Fig. 1 as the RCA territory remote from the incision line of EVCPP. QGS study was performed before surgery, early postoperatively (group B: 44±47, group N: 22±7 days after surgery) and mid-term postoperatively (group B: 38±7, group N: 27±12 months after surgery).
2.4. Statistical analysis
All results were reported as mean±standard deviation. The paired t-test was used for comparisons between preoperative and early-postoperative values, and between early and mid-term postoperative values. The unpaired t-test was used for the comparison of values between group B and group N. A P-value of less than 0.05 was considered statistically significant.
3. Results
3.1. Comparsion in wall thickening
3.1.1. Segment 7 (Table 2)
There was no significant difference between preoperative values and early postoperative values, and between early and mid-term postoperative values in either group. Furthermore, there was no significant difference between group B and group N at any time point.
3.1.2. Segment 8 (Table 3)
No significant difference between preoperative and early postoperative values was seen in both groups. However, significant differences were observed between the early and mid-term postoperative values in both groups. Although there was a significant difference between group B and group N preoperatively, there was no significant difference between group B and group N in the early and mid-term postoperative periods.
3.1.3. Segment 10 (Table 4)
Although a significant difference between the preoperative value and early postoperative value was seen in group B, no significant difference between the early and mid-term postoperative values was seen in the same group. In group N, there was no significant difference between the preoperatively and early postoperatively, but there was a significant difference between the early and mid-term postoperatively. Though no significant difference between group B and group N was seen preoperatively and early postoperatively, a significant difference between group B and group N was found in the mid-term postoperative period.
3.1.4. Segment 11 (Table 5)
There was no significant difference between the preoperative and early postoperative values in group B, but there was a significant difference between the early and mid-term postoperative values. Also in group N, there was no significant difference between preoperatively and early postoperatively, but there was a significant difference between the early and mid-term postoperatively. As in segment 8, there was a significant difference between group B and group N preoperatively, but there were no significant early postoperative and mid-term postoperative differences.
4. Discussion
Kramer and co-workers suggested that the mechanical effects of the aneurysm on noninfarcted regions is caused by elevated local wall stress in an ovine model of LV anteroapical aneurysm and that intramyocardial function remained depressed in noninfarcted regions adjacent to the aneurysm [9]. An increase in compliance leads to increased wall stress and decreased global mechanical performance [5]. However, LV aneurysm resection leads to improvement in remote regional performance due to reductions in local wall stress in the remote regions [4,5]. Our study revealed that wall function improved significantly in the mid-term period after surgery in patients without RCA territory disease. This result indicates that EVCPP improves remote regional function as reported by Di Donato [4] and Kramer [5].
Furthermore, the present study revealed that the percent increase in wall thickness in group B was worse than that in group N, but that the percent increase in group B improved, as in group N, after surgery. Since oxygen consumption is directly related to myocardial stress [10], oxygen demand in the remote noninfarcted muscle in- creases. Moreover, the existence of coronary artery lesions decreases oxygen supply. We believe that the supply imbalance resulted in a lower percent increase in wall thickness in group B. The marked decrease in left ventricular volume reduces not only wall tension but also oxygen demand [11]. We believe that the reduction in wall tension and oxygen demand by EVCPP and the increase of oxygen supply by CABG produced dramatic improvements in the percent increase in wall thickness in group B. These results indicate that revascularization to the RCA is very important [12].
Kramer and co-authors demonstrated that the improvement of LV function after LV aneurysm repair is most marked in the middle of the left ventricle and the base and inferior wall remote from the aneurysm [5]. Di Donato and co-workers reported that postoperative functional improvement is mainly related to the increase in inferior LV wall motion [12]. Our present study also shows that wall thickening in the basal inferior and/or posterior wall improves in the mid-term period after EVCPP. Our previous study demonstrated that the improvement of LV systolic function is maintained not only in the early period but also in the mid-term period after EVCPP [13]. We believe that the improvement in LV function after EVCPP is caused by a marked reduction in volume and increased inferior LV wall motion in the early period after EVCPP. We believe that the process of reverse remodeling continues in the mid-term period.
References
McKay RG, Pfeffer MA, Pasternak RC, Markis JE, Come PC, Nakao S, Alderman JD, Ferguson JJ, Safian RD, Grossman W. Left ventricular remodeling after myocardial infarction: a corollary to infarct expansion. Circulation 1986;74:693–702.
Pfeffer MA, Braunwald E. Ventricular remodeling after myocardial infarction. Circulation 1990;81:1161–1172.
Bogen DK, Rabinowitz SA, Needleman A, McMahon TA, Abelmann WH. An analysis of the mechanical disadvantage of myocardial infarction in the canine left ventricle. Circ Res 1980;47:728–741.
Di Donato M, Sabatier M, Toso A, Barletta G, Baroni M, Dor V, Fantini F. Regional myocardial performance of non-ischaemic zones remote from anterior wall left ventricular aneurysm. Effect of aneurysmectomy. Eur Heart J 1995;16:1285–1292.
Kramer CM, Magovern JA, Rogers WJ, Vido D, Savage EB. Reverse remodeling and improved regional function after repair of left ventricular aneurysm. J Thorac Cardiovasc Surg 2002;123:700–706.
Yoshioka J, Hasegawa S, Yamaguchi H, Tokita N, Paul AK, Xiuli M, Maruyama A, Hori M, Nishimura T. Left ventricular volumes and ejection fraction calculated from quantitative elactrocardiographic-gated 99mTC-tetrofosmin myocardial SPECT. J Nucl Med 1999;40:1693–1698.
Kondo C, Fukushima K, Kusakabe K. Measurement of left ventricular volumes and ejection fraction by quantitative gated SPET, contrast ventriculography and magnetic resonance imaging: a meta-analysis. Eur J Nucl Med Mol Imaging 2003;30:851–858.
Germano G, Erel J, Lewin H, Kavanagh PB, Berman DS. Automatic quantitation of regional myocardial wall motion and thickening from gated technetium-99 m sestamibi myocardial perfusion single-photon emission computed tomography. J Am Coll Cardiol 1997;30:1360–1367.
Kramer CM, Lima JAC, Reichek N, Frrari VA, Llaneras MR, Palmon LC, Yah IT, Tallant B, Axel L. Reginal function within non-infarcted myocardium during left ventricular remodeling. Circulation 1993;88:1279–1288.
Maroko PR, Braunwald PR. Modification of myocardial infarction size after coronary occlusion. Ann Int Med 1973;79:720–733.
Di Donato M, Sabatier M, Dor V, Toso A, Maioli M, Fantini F. Akinetic vs. dyskinetic postinfarction scar: relation to surgical outcome in patients undergoing endoventricular circular patch plasty repair. J Am Coll Cardiol 1997;29:1569–1575.
Di Donato M, Barletta G, Maioli M, Fantini F, Coste P, Sabatier M, Montiglio F, Dor V. Early hemodynamic results of left ventricular reconstructive surgery for anterior wall left ventricular aneurysm. Am J Cardiol 1992;69:886–890.
Fujii H, Ohashi H, Tsutsumi Y, Kawai T, Iino K, Onaka M. Radionuclide study of mid-term left ventricular function after endoventricular circular patch plasty. Eur J Cardio-thorac Surg 2004;26:125–128.(Hiromichi Fujii, Hirokazu)