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Prevalence of myocardial viability as detected by positron emission tomography in patients with ischemic cardiomyopathy
LITERATURE REVIEW Linda Shore-Lesserson, MD
VENTRICULAR ASSIST DEVICES
McBride LR, Naunheim KS, Fiore AC, et al: Clinical experience with 111 Thoratec ventricular assist devices. Ann Thorac Surg 67:1233-1239, 1999 These investigators described their experience with the Thoratec ventricular assist device (VAD) for patients recovering from myocardial shock (n = 44) and as a bridge to transplantation (n = 65). Patients were considered for placement of the Thoratec VAD when they remained hemodynamically unstable after preload optimization, maximal inotropic support, or placement of an intra-aortic balloon pump. Nineteen (43%) of the recovery patients were weaned from the VAD, and 12 (27%) were discharged home, whereas 39 (58%) of the bridge group were successfully transplanted and discharged home. Bleeding (45% and 31%) and infection (39% and 49%) were the most common complications in the recovery and bridge groups, respectively. Implication: The Thoratec VAD can be used for myocardial shock recovery and as a bridge to transplantation.
Rose EA, Moskowitz A J, Packer M, et ah The REMATCH trial: Rationale, design, and end points. Ann Thorac Surg 67:723-730, 1999 The REMATCH (Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure) trial is a multicenter trial designed to evaluate prospectively outcomes in patients ineligible for cardiac transplantation who are randomly treated with either medical management or an implantable ventricular assist device (I-IeartMate, Vented Electric version, Thermo Cardiosystems Inc). Ineligibility for cardiac transplant was defined as age greater than 65 years, insulinrequiring diabetes mellitus with end-organ damage, chronic renal failure, or other major comorbidity. Difficulties in randomizing such a high-risk patient group and the problems with crossover during the study are discussed. End points include survival, quality of life scores, and cost-effectiveness. Implication: The success and cost-effectiveness of implanted ventricular assist devices can be improved by what is learned through the conduction of multicenter, randomized trials.
Chen JM, DeRose J J, Slater JP, et ah Improved survival rates support left ventricular assist device implantation early after myocardial infarction. J Am Coil Cardiol 33:1903-1908, 1999 Implantation of a left ventricular assist device (LVAD) after myocardial infarction has traditionally been performed after 2 weeks (late) to allow for hemodynamic and end-organ stabilization. Early insertion of an LVAD may provide for a greater degree of myocardial salvage. Patients who had an LVAD inserted sooner than 2 weeks after myocardial infarction (n = 15) were compared with patients who had the device inserted after 2 weeks (n = 10) with respect to demographics, use of a right ventficular assist device, use of inhaled nitric oxide, perioperative hemodynamics, and survival statistics. Patients who had early insertion of an LVAD had more frequently suffered a failed surgical revascularization. This group used fewer right ventricniar assist devices but were 794
administered more nitric oxide. Patients in the early group had a mortality of 26% compared with a mortality of 40% in the late group. Implication: Appropriate patient selection may allow patients with acute myocardial infarction to benefit from a greater degree of myocardial recovery if a LVAD is inserted early rather than after a 2-week stabilization period.
CARDIOMYOPATHY
Pauschinger M, Knopf D, Petschauer S, et ah Dilated cardiomyopathy is associated with significant changes in collagen type I/III ratio. Circulation 99: 2750-2756, 1999 Thirty patients with dilated cardiomyopathy were evaluated for changes in collagen within the myocardial matrix. Cardiac catheterization was performed to determine cardiac function (ejection fraction > 50%, n = 18, and ejection fraction < 50%, n = 12), and endomyocardial biopsy specimens were taken from the right ventricle. Gene expression of Col I (stiffness), Col III, and transforming growth factors (TGF)-[31 and [32 were analyzed from the endomyocardial biopsy specimens, and all patients were compared. Patients with an ejection fraction less than 50% demonstrated a higher amount of mRNA for Col I and Col III, a higher total collagen content, and a higher ratio of the Col I to Col III in gene expression and protein synthesis. There was also an increase in mRNA of TGF-131 and TGF-[32. Implication: The myocardial matrix may be remodeled in patients with dilated cardiomyopathy, which may contribute to systolic and diastolic dysfunction.
Auerbach MA, Schoder H, Hoh C, et ah Prevalence of myocardial viability as detected by positron emission tomography in patients with ischemic cardiomyopathy. Circulation 99:2921-2926, 1999 Hypoperfused viable myocardium improves contractile performance after revascularization. The presence of viable myocardium in patients with ischemic cardiomyopathy was evaluated in 283 patients by blood flow-to-metabolism ratios assessed by tomography. Correlation of viability with clinical or demographic predictors was sought. Of patients, 41% had nonviable myocardium, 55% had viable segments, and 4% had normal perfusion. Multivariate analysis revealed no association of viability with age, sex, history of revascularization, myocardial infarction, angina, diabetes, ventricular size, and ventricular function. Logistic regression revealed that patients with angina had a larger number of viable segments, which deemed the viability "functionally significant." Implication: Coronary revascularization may benefit patients with ischemic cardiomyopathy because of the presence of viable myocardium.
Maron B J, Nishimura RA, McKenna WJ, et ah Assessment of permanent dual-chamber pacing as a treatment for drug-refractory symptomatic patients
Journal of Cardiothoracic and Vascular Anesthesia, Vo113, No 6 (December), 1999: pp 794-796
VENTRICULAR ASSIST DEVICES
McBride LR, Naunheim KS, Fiore AC, et al: Clinical experience with 111 Thoratec ventricular assist devices. Ann Thorac Surg 67:1233-1239, 1999 These investigators described their experience with the Thoratec ventricular assist device (VAD) for patients recovering from myocardial shock (n = 44) and as a bridge to transplantation (n = 65). Patients were considered for placement of the Thoratec VAD when they remained hemodynamically unstable after preload optimization, maximal inotropic support, or placement of an intra-aortic balloon pump. Nineteen (43%) of the recovery patients were weaned from the VAD, and 12 (27%) were discharged home, whereas 39 (58%) of the bridge group were successfully transplanted and discharged home. Bleeding (45% and 31%) and infection (39% and 49%) were the most common complications in the recovery and bridge groups, respectively. Implication: The Thoratec VAD can be used for myocardial shock recovery and as a bridge to transplantation.
Rose EA, Moskowitz A J, Packer M, et ah The REMATCH trial: Rationale, design, and end points. Ann Thorac Surg 67:723-730, 1999 The REMATCH (Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure) trial is a multicenter trial designed to evaluate prospectively outcomes in patients ineligible for cardiac transplantation who are randomly treated with either medical management or an implantable ventricular assist device (I-IeartMate, Vented Electric version, Thermo Cardiosystems Inc). Ineligibility for cardiac transplant was defined as age greater than 65 years, insulinrequiring diabetes mellitus with end-organ damage, chronic renal failure, or other major comorbidity. Difficulties in randomizing such a high-risk patient group and the problems with crossover during the study are discussed. End points include survival, quality of life scores, and cost-effectiveness. Implication: The success and cost-effectiveness of implanted ventricular assist devices can be improved by what is learned through the conduction of multicenter, randomized trials.
Chen JM, DeRose J J, Slater JP, et ah Improved survival rates support left ventricular assist device implantation early after myocardial infarction. J Am Coil Cardiol 33:1903-1908, 1999 Implantation of a left ventricular assist device (LVAD) after myocardial infarction has traditionally been performed after 2 weeks (late) to allow for hemodynamic and end-organ stabilization. Early insertion of an LVAD may provide for a greater degree of myocardial salvage. Patients who had an LVAD inserted sooner than 2 weeks after myocardial infarction (n = 15) were compared with patients who had the device inserted after 2 weeks (n = 10) with respect to demographics, use of a right ventficular assist device, use of inhaled nitric oxide, perioperative hemodynamics, and survival statistics. Patients who had early insertion of an LVAD had more frequently suffered a failed surgical revascularization. This group used fewer right ventricniar assist devices but were 794
administered more nitric oxide. Patients in the early group had a mortality of 26% compared with a mortality of 40% in the late group. Implication: Appropriate patient selection may allow patients with acute myocardial infarction to benefit from a greater degree of myocardial recovery if a LVAD is inserted early rather than after a 2-week stabilization period.
CARDIOMYOPATHY
Pauschinger M, Knopf D, Petschauer S, et ah Dilated cardiomyopathy is associated with significant changes in collagen type I/III ratio. Circulation 99: 2750-2756, 1999 Thirty patients with dilated cardiomyopathy were evaluated for changes in collagen within the myocardial matrix. Cardiac catheterization was performed to determine cardiac function (ejection fraction > 50%, n = 18, and ejection fraction < 50%, n = 12), and endomyocardial biopsy specimens were taken from the right ventricle. Gene expression of Col I (stiffness), Col III, and transforming growth factors (TGF)-[31 and [32 were analyzed from the endomyocardial biopsy specimens, and all patients were compared. Patients with an ejection fraction less than 50% demonstrated a higher amount of mRNA for Col I and Col III, a higher total collagen content, and a higher ratio of the Col I to Col III in gene expression and protein synthesis. There was also an increase in mRNA of TGF-131 and TGF-[32. Implication: The myocardial matrix may be remodeled in patients with dilated cardiomyopathy, which may contribute to systolic and diastolic dysfunction.
Auerbach MA, Schoder H, Hoh C, et ah Prevalence of myocardial viability as detected by positron emission tomography in patients with ischemic cardiomyopathy. Circulation 99:2921-2926, 1999 Hypoperfused viable myocardium improves contractile performance after revascularization. The presence of viable myocardium in patients with ischemic cardiomyopathy was evaluated in 283 patients by blood flow-to-metabolism ratios assessed by tomography. Correlation of viability with clinical or demographic predictors was sought. Of patients, 41% had nonviable myocardium, 55% had viable segments, and 4% had normal perfusion. Multivariate analysis revealed no association of viability with age, sex, history of revascularization, myocardial infarction, angina, diabetes, ventricular size, and ventricular function. Logistic regression revealed that patients with angina had a larger number of viable segments, which deemed the viability "functionally significant." Implication: Coronary revascularization may benefit patients with ischemic cardiomyopathy because of the presence of viable myocardium.
Maron B J, Nishimura RA, McKenna WJ, et ah Assessment of permanent dual-chamber pacing as a treatment for drug-refractory symptomatic patients
Journal of Cardiothoracic and Vascular Anesthesia, Vo113, No 6 (December), 1999: pp 794-796