RESUMO
BACKGROUND: Myocardial perfusion imaging with dipyridamole is an alternative with which to evaluate patients who are unable to exercise. Many patients who undergo dipyridamole testing are limited in their ability, but are not completely unable, to exercise. There are benefits from adding low workload exercise to dipyridamole testing, including a reduction of thallium 201 concentration in the liver, leading to a higher heart-to-liver activity ratio and better image quality. This prospective study was designed to evaluate a protocol of exercise supplementation during dipyridamole technetium 99m sestamibi imaging and to verify whether a higher heart-to-liver activity ratio could be obtained. We also evaluated the potential of this combined protocol to prevent hypotension and induce ischemic changes on the electrocardiogram (ECG). METHODS AND RESULTS: Ninety consecutive patients who were not completely disabled for exercise underwent dipyridamole Tc-99m sestamibi cardiac single photon emission computed tomography with a protocol of exercise supplementation (DipEx). The heart-to-liver activity ratio, hemodynamics, and electrocardiographic changes were studied. The findings were compared with those of a control group (Dip) composed of 99 patients who underwent dipyridamole infusion alone. Patients with left bundle branch block, pacemaker, and atrial fibrillation were excluded. The DipEx patients tolerated the protocol, exercising 4.2 +/- 1.3 minutes on the treadmill (Bruce protocol). Compared with Dip, patients in the DipEx group had a higher heart-to-liver activity ratio (1.3 +/- 0.4 vs 1.6 +/- 0.5, respectively; P =.00001), had no incidence of hypotension (6% vs 0%, respectively; P =.03), and had a higher sensitivity of the ECG to detect ischemia (6% vs 34%, respectively; P =.003). The increase in sensitivity seen in the DipEx group was accompanied by a significant decrease in specificity compared with the Dip group (67% vs 100%, P =.000001). CONCLUSIONS: Our data show that the addition of limited exercise to dipyridamole results in benefits during Tc-99m sestamibi imaging, increasing heart-to-liver activity ratio, preventing vasodilator-induced hypotension, and improving ECG sensitivity for the detection of ischemia. Furthermore, this protocol also provides an estimation of the patient's physical capacity and could be used as an alternative for patients undergoing dipyridamole infusion who are not completely unable to exercise.
Assuntos
Dipiridamol/uso terapêutico , Eletrocardiografia/efeitos dos fármacos , Teste de Esforço/efeitos dos fármacos , Teste de Esforço/métodos , Coração/diagnóstico por imagem , Coração/fisiopatologia , Hipotensão/prevenção & controle , Fígado/diagnóstico por imagem , Fígado/fisiopatologia , Isquemia Miocárdica/diagnóstico por imagem , Isquemia Miocárdica/fisiopatologia , Compostos Radiofarmacêuticos , Tecnécio Tc 99m Sestamibi , Vasodilatadores/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Hemodinâmica/efeitos dos fármacos , Hemodinâmica/fisiologia , Humanos , Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Sensibilidade e Especificidade , Tomografia Computadorizada de Emissão de Fóton Único , Avaliação da Capacidade de TrabalhoRESUMO
Erysipelas (cellulitis/lymphangitis) is a superficial cutaneous infection spread by the lymphatic system which may result in permanent injury to the lymphatic vessels. The study evaluated the lymphatic drainage in the lower limbs of 30 patients with at least two episodes of erysipelas by means of lymphoscintigraphy. Twenty-two (73%) were female and 8 (27%) were male with ages ranging from 26 to 77 years (mean 52 years). Lymphoscintigraphy was performed by intradermal administration of 500 microCi (20 Mbq) of 99mTc antimony sulfur-colloid in two interdigital spaces of the feet. Whole body scintigraphy was performed 45 minutes after the administration of the radiopharmaceutical using a computerized gamma camera. Significant lymphatic abnormalities were found in 23 (77%) of these patients. We conclude that most patients with repeated erysipelas have significant and even permanent abnormalities in regional lymphatic drainage. Recurrent erysipelas suggests underlying primary or secondary lymphedema.