[Diagnostic accuracy of tomographic myocardial imaging for evaluation of aortocoronary graft patency]

INTRODUCTION AND OBJECTIVES

Conventional ergometry has limitations in the evaluation of coronary artery bypass graft patency. The aim of the present study was to determine the efficacy of exercise single photon emission tomography with 99mTc-compounds for the diagnosis of coronary artery bypass grafts disease.

PATIENTS AND METHODS

The state of sixty-seven coronary artery bypass grafts (31 with mammary artery, 36 with safein vein; 35 to left descending anterior artery, 15 to circumflex and 17 to right coronary artery) were analyzed retrospectively in 38 patients (mean age 63+/-8.7; 35 men). The time that elapsed between the coronary surgery and the exercise tomography was 9,7 years. In 16 cases, exercise tomography was performed with 99mTc-MIBI and in the 22 remaining with 99mTc-tetrofosmin. In 6 cases, dipiridamol was administred simultaneously during an insufficient exercise test.

RESULTS

Sensitivity (73.1%), specificity (93%), positive predictive value (86.3%), negative predictive value (84.4%), global value (85%), positive likelihood ratio (10.4) and negative likelihood ratio (0.29) of exercise tomography were significantly (p<0.01) better than those obtained with the exercise test alone (53.8%, 43.6%, 38.9%, 58. 6%, 47.7%, 0.95 and 1.06, respectively).

CONCLUSIONS

Exercise tomography with 99mTc-compounds is a highly effective for the detection of coronary artery bypass grafts disease.

[De-novo reversible stenoses in tortuous arteries during coronary angioplasty due to the accordion effect. A clinical case and review of the literature]

During the performance of PTCA, the operator must be able to differentiate true complications from pseudocomplications. Mechanical coronary shortening and vessel wall invagination due to accordion effect, "pseudo-transection", dissection, coronary spasm, and localized thrombosis are sources of iatrogenic obstruction during angioplasty. We report a case in which straightening of a right tortuous coronary artery during angioplasty produced an iatrogenic lesion that has a typical invaginate appearance. Conservative management is indicated in the absence of definitive angiographic aspect of vessel trauma, because they disappear after withdrawal of angioplasty equipment or adequate management of the guidewire.

[Prosthesis-related thrombosis cleared with fibrinolysis. Usefulness of transesophageal echocardiography]

Thrombosis is an infrequent complication in mechanical valve prostheses carrying a vital risk for the patient. The performance of transesophageal echocardiography (TEE) is high in differentiating the thrombosis from other causes of flow obstruction and is fundamental for establishing treatment. Fibrinolysis is an effective alternative treatment to surgery when the latter carries a high risk. In the case herein reported TEE provided a rapid and precise diagnosis and allowed to prove the resolution of the prosthetic thrombosis following fibrinolytic treatment.