A dor torácica é um achado comum em pacientes com cardiomiopatia hipertrófica e pode ser observada em 40% a 50% de todos os pacientes. No entanto, a patogênese destes sintomas isquemia símile ainda permanece sem esclarecimento.
Em um estudo publicado recentemente na Journal of Thoracic and Cardiovascular Surgery, vinte e dois pacientes com cardiomiopatia hipertrófica e 15 controles foram submetidos a tomografia por emissão de pósitrons para avaliação da perfusão miocárdica regional e do fluxo de reserva coronária (fluxo sanguíneo miocárdico hiperêmico/basal).
A perfusão miocárdica (mL/min/g) foi medida através da concentração de amônia [13N] no repouso e durante a hiperemia com dipiridamol (0.56 mg/kg intravenosamente). A reserva e fluxo regional da coronária foi avaliada em planos (apical, médio ventricular e basal) em quatro regiões (septal, anterior, lateral e inferior). Os pacientes foram divididos em dois grupos: o grupo 1 consistiu-se de onze pacientes tratados com miectomia cirúrgica (idade 56 ± 10 anos) e o grupo 2 consistiu-se de onze pacientes tratados com medicação (idade 53 ± 13 anos).
A média global do fluxo de reserva coronária foi de 3.87 ± 0.92 nos controles, porém 2.31 ± 0.40 nos operados (P < .001 vs controles) e 1.76 ± 0.58 nos pacientes tratados com medicação (P < .001 vs controles, P < .05 vs operados). Similarmente, o fluxo de reserva coronária septal foi de 4.19 ± 1.22 nos controles, porém reduziu significativamente nos pacientes operados (2.26 ± 0.48, P < .001 vs controles) e nos pacientes tratados com medicação (1.76 ± 0.58; P < .001 vs controles). O fluxo de reserva septal foi significativamente maior nos pacientes operados do que nos pacientes com cardiomiopatia hipertrófica tratada com medicação (+37%, P < .05), principalmente devido a uma reduzida perfusão miocárdica de repouso.
Os autores concluíram que a perfusão miocárdica global e regional está reduzida nos pacientes com cardiomiopatia hipertrófica. No entanto, a miomectomia pode ter um efeito benéfico sobre a perfusão septal e fluxo de reserva. Portanto, a isquemia parece desempenhar um importante papel na sintomatologia e patofisiologia da cardiomiopatia hipertrófica.
Regional myocardial ischemia in hypertrophic cardiomyopathy: Impact of myectomy - The Journal of Thoracic and Cardiovascular Surgery 2004;128:163-169
Thorac Cardiovasc Surg 2004;128:163-169
© 2004 Mosby, Inc.
Cardiopulmonary support and physiology |
Regional myocardial ischemia in hypertrophic cardiomyopathy: Impact of myectomy
Manuela Jörg-Ciopor, MDb, Mehdi Namdar, MDb, Jurai Turina, MDa, Rolf Jenni, MD, MSEEa, Jürg Schwitter, MDa, Marko Turina, MDc, Otto M. Hess, MDd, Philipp A. Kaufmann, MDb,*
a Department of Cardiology, University Hospital, Zürich, Switzerland
b Department of Nuclear Cardiology, University Hospital, Zürich, Switzerland
c Department of Cardiothoracic Surgery, University Hospital, Zürich, Switzerland
d Department of Cardiology, Swiss Heart Center, Berne, Switzerland
Received for publication April 21, 2003; revisions received July 12, 2003; accepted for publication November 4, 2003. * Address for reprints: Philipp Kaufmann, MD, Head, Nuclear Cardiology, Cardiovascular Center, University Hospital C NUK 32, Rämistr. 100, CH—8091 Zürich, Switzerland
pak@usz.ch
OBJECTIVE: Chest pain is a common finding in patients with hypertrophic cardiomyopathy and can be observed in 40% to 50% of all patients. However, the pathogenesis of these ischemia-like symptoms is still unclear.
METHODS: Twenty-two patients with hypertrophic cardiomyopathy and 15 controls underwent positron emission tomography for evaluation of regional myocardial perfusion and coronary flow reserve (hyperemic/baseline myocardial blood flow). Myocardial perfusion (mL/min/g) was measured using [13N]ammonia at rest and during hyperemia with dipyridamole (0.56 mg/kg intravenously). Regional coronary flow reserve was assessed in 3 planes (apical, midventricular, basal) in 4 regions (septal, anterior, lateral, inferior). Patients were divided into 2 groups: group 1 consisted of 11 patients treated with surgical myectomy (age 56 ± 10 years) and group 2 consisted of 11 patients treated medically (age 53 ± 13 years).
RESULTS: Mean global coronary flow reserve was 3.87 ± 0.92 in controls but 2.31 ± 0.40 in operated (P < .001 vs controls) and 1.76 ± 0.58 in medically treated patients (P < .001 vs controls, P < .05 vs operated). Similarly, septal coronary flow reserve was 4.19 ± 1.22 in controls but significantly reduced in operated patients (2.26 ± 0.48, P < .001 vs controls) and in medically treated patients (1.76 ± 0.58; P < .001 vs controls). However, septal flow reserve was significantly higher in operated patients than in patients with medically treated hypertrophic cardiomyopathy (+37%, P < .05), mainly due to a reduced resting myocardial perfusion.
CONCLUSIONS: Global and regional myocardial perfusion is reduced in patients with hypertrophic cardiomyopathy. However, myectomy may have a beneficial effect on septal perfusion and flow reserve. Thus, ischemia seems to play an important role in the symptomatology and pathophysiology of hypertrophic cardiomyopathy.
