Dobutamine stress magnetocardiography for the detection of significant coronary artery stenoses - a prospective study in comparison with simultaneous 12-lead electrocardiography.

BACKGROUND: Exercise electrocardiography is an imperfect test for the detection of coronary artery disease (CAD). Magnetocardiography detects cardiac electrical disturbances associated with myocardial ischemia. We prospectively investigated the accuracy of high-dose dobutamine stress magnetocardiography (DS-MCG) and simultaneous electrocardiography (DS-ECG) for the detection of significant CAD. METHODS: 100 patients with an intermediate pre-test probability for CAD underwent DS-MCG using a multichannel magnetometer prior to invasive coronary angiography. Patients were examined at rest and during a standard dobutamine-atropine scheme. Significant reduction of epicardial current strength/density during stress, reconstructed from the magnetic field map and superposed on a virtual heart model indicates myocardial ischemia. A 12-lead DS-ECG was recorded simultaneously. Significant coronary artery stenosis was defined as > or = 70% of lumen reduction. RESULTS: Without beta-blocker all 100 patients reached the targeted heart rate. The image quality of DS-MCG and DS-ECG was sufficient for analysis in all patients. In 19 patients CAD was ruled out angiographically. Thirty two or seven patients revealed coronary artery stenoses of 30-49% or of 50-69%, respectively. In 42 patients we found significant stenoses of > or = 70%. In 41 of these patients DS-MCG revealed myocardial ischemia. The sensitivity of DS-MCG and DS-ECG for the detection of significant coronary artery stenosis was 97.6% and 26.2%, the specificity of DS-MCG and DS-ECG 82.8% and 82.8%, respectively. CONCLUSIONS: DS-MCG can be performed with a standard dobutamine/atropine stress protocol. DS-MCG yields a significantly higher accuracy for the detection of significant coronary artery stenosis than DS-ECG.

[Treatment of pseudoaneurysms with injection of thrombin]. / Liecba pseudoaneuryziem injekciou trombínu.

OBJECTIVES: To introduce and assess the efficacy and risks associated with a new treatment method of post-catheterization pseudoaneurysms. METHODS: Thrombin injection was indicated in patients with failure of compression therapy during 24 hours. Patients with a cavity volume < 1 cm3, with a pseudoaneurysm causing compression or haemorrhagic shock were excluded. A needle is introduced under local anaesthesia with ultrasound guidance, its tip is placed thoroughly in the centre of the cavity. Subsequently, under colour-flow mapping, thrombin solution with concentration of 1000 IU/ml is cautiously injected, which results in instantaneous thrombosis of the pseudoaneurysm cavity. RESULTS: Thrombin injection was used in 17 patients during a period of 12 months. 12 of them were women, 6 patients with valvular disease, 2 after intervention and 5 anticoagulated. The method was successful in 16 patients. In 5 of them, a small residual cavity persisted, which was not suitable for re-injection, and was closed completely after a few minutes of compression by a ultrasound transducer. There were no thrombotic complications. CONCLUSION: Although compression remains the method of choice, thrombin injection is a highly effective, quick and, with necessary precautions, safe alternative to surgical treatment of pseudoaneurysms, mainly in anticoagulated patients.

The internal mammary artery bypass--the principles of preoperative and postoperative diagnosis using colour-duplex ultrasound.

BACKGROUND: The aim of the study was the assessment of functional characteristics of the left internal mammary artery (LIMA) bypass in patients after coronary artery bypass grafting (CABG) in comparison with the native LIMA using colour-duplex ultrasound as the non-invasive diagnostic method. METHODS: We examined 303 patients after myocardial revascularization with the internal mammary artery bypass using the Hewllett Packard 2500, 5500 ultrasound units. Using the 7.5 MHz linear transducer we detected the LIMA from the left supraclavicular approach. We assessed the peak systolic velocity (PSV--cm/s), peak diastolic velocity (PDV--cm/s), end-diastolic velocity (EDV--cm/s) and we calculated the peak systolic/peak diastolic velocity ratio (SDVR) and resistance index RI (PSV-EDV/PSV). The obtained parameters were compared with the native LIMA flow characteristics of the 70 consecutive patients before CABG. RESULTS: We observed the transformation of internal mammary artery flow from the predominantly systolic high resistance type of the native LIMA, to the low resistance biphasic waveform after its use as a coronary artery graft. We detected a significant increase of diastolic flow velocities and a significant decrease of resistance and of the SDVR ratio. In dysfunctional grafts we found a decrease of diastolic flow and an increase of LIMA resistance and SDVR. CONCLUSION: The colour-duplex ultrasound is a perspective non-invasive method for the postoperative follow-up of patients with the LIMA graft. It allows the assessment of the bypass flow characteristics, functional status and patency and it could contribute to the early diagnosis of bypass failure. (Fig. 6, Tab. 4, Ref. 21.)