In vivo magnetic resonance imaging and surgical histopathology of intracardiac masses: distinct features of subacute thrombi

We evaluated intracardiac masses in vivo, in situ and histologically to determine tissue properties revealed by magnetic resonance (MR) imaging. In 15 consecutive patients scheduled for cardiotomy, the cardiac chambers were studied preoperatively with MR imaging and echocardiography. Visual examination of one or more chambers was performed during cardiotomy for mitral valve replacement, aneurysmectomy, atrial septal repair and atriotomy. Six thrombi (1 atrial appendage, 5 ventricular) and 2 atrial myxomas were removed and subjected to histological analysis. All masses were detected preoperatively by MR imaging. The smallest was a subacute 3-mm mural clot in the left ventricle and was undetected by transesophageal and transthoracic echocardiography. The 3 subacute clots had homogeneously low MR signals, did not enhance with gadolinium and exhibited magnetic susceptibility effects; histopathology confirmed these clots to be avascular and laden with dense iron deposition related to hemoglobin breakdown products. The 3 organized clots had intermediate and heterogeneous MR signals and multiple areas of gadolinium enhancement. The 2 myxomas had low MR signals and gadolinium enhancement in the core and septal attachment; these areas had dense neovascular channels. Subacute thrombi appear to have MR features that are distinct from organized thrombi and myxomas, and MR images of subacute thrombi contrast sharply with normal cardiac structures, enabling detection of thin mural clots that may be echographically occult. These findings may be of value, because a subacute clot may be more likely than an organized thrombus to give rise to an embolus.

Clinical and hemodynamic performance of the Ionescu-Shiley valve in the small aortic root. Results in 117 patients with 17 and 19 mm valves

The Ionescu-Shiley pericardial valve was our bioprosthetic valve of choice between 1981 and 1985 for patients in whom the aortic anulus could not accept a valve larger than 19 mm in outer diameter or in whom the avoidance of warfarin sodium (Coumadin) was important. A series of 117 consecutive patients who received 17 or 19 mm valves for isolated aortic valve replacement or aortic valve replacement combined with coronary artery bypass grafting or other valvular procedures was analyzed. Overall, 74% of the patients were female, with a mean age of 70.9 years and a body surface area of 1.67 +/- 0.19 m2; 92.3% were in New York Heart Association class III-IV, and the operation was urgent or emergent in 46%. The operative mortality rate was 7.7%, with no deaths in patients undergoing isolated elective first-time aortic valve replacement. Mean follow-up for survivors was 2.5 years (10 to 62 months). There were 20 late deaths, of which three were valve related, three were due to sudden death or arrhythmias, and two were due to persistent heart failure. The actuarial survival rate at 5 years was 68%. Clinical follow-up revealed a low incidence of valve-related complications, and 96.4% of survivors were in class I-II. Postoperative echocardiography before hospital discharge revealed a maximum instantaneous gradient of 18.4 +/- 3.0 mm Hg in five patients having a 17 mm valve and 31.3 +/- 12.7 mm Hg in 20 patients having a 19 mm valve. Doppler echocardiography was performed in 22 patients at a mean follow-up of 39.3 +/- 11.7 months. The maximum instantaneous gradient was 25 +/- 17.2 mm Hg for 17 mm and 17.41 +/- 5.4 mm Hg for 19 mm valves at late follow-up. The effective orifice area was 0.85 +/- 0.1 cm2 for 17 mm and 1.21 +/- 0.21 cm2 for 19 mm valves. This study defines the normal range of Doppler echocardiographic transprosthetic gradients for the Ionescu-Shiley valve and confirms that low operative mortality and excellent clinical improvement can result from the use of small Ionescu-Shiley valves in elderly patients despite moderate postoperative transvalvular gradients.

Successful repair of postoperative ascending aortic mycotic false aneurysms using circulatory arrest

Mediastinal wound infections following open-heart operations are successfully managed in most patients by aggressive debridement and placement of substernal drainage catheters or application of omental or muscle flaps. Nonetheless, the involvement of foreign bodies, such as felt pledgets adjacent to cardiac structures, can result in infections that persist despite flap coverage and can present as mycotic false aneurysms of the ascending aorta. We present the cases of 3 patients who underwent successful repair of such aneurysms late after surgical treatment of mediastinal wound infections. We describe our technique of repair using groin cannulation for bypass, moderate hypothermia, and circulatory arrest to improve exposure and minimize bleeding.

Efficacy of retrograde coronary sinus cardioplegia in patients undergoing myocardial revascularization: a prospective randomized trial

The efficacy of retrograde coronary sinus cardioplegia (RCSC) administered through the right atrium compared with aortic root cardioplegia (ARC) has not been examined critically in patients undergoing coronary artery bypass grafting (CABG). Twenty patients having elective CABG were randomized prospectively to receive cold blood ARC (Group I, 10 patients) or cold blood RCSC (Group II, 10 patients). Patient demographics were similar in both groups. Ventricular function was assessed preoperatively by radionuclide ventriculography and postoperatively by simultaneous hemodynamic and radionuclide ventriculographic studies with volume loading. There was no change in ejection fraction (EF) (preoperative versus postoperative value) in Group I (50 +/- 6% versus 53 +/- 6%) but in group II, at similar peak systolic pressure and similar left ventricular end-diastolic volume index (LVEDVI), LVEF improved significantly (49 +/- 6% versus 60 +/- 12%, p less than 0.05). Postoperative ventricular function (stroke work index versus EDVI) for the left ventricle and right ventricle were similar in both groups. Evaluation of postoperative LV systolic function (end-systolic blood pressure versus end-systolic volume index) and diastolic function (pulmonary capillary wedge pressure versus EDVI) were also similar in both groups. Retrograde coronary sinus cardioplegia is as effective as ARC for intraoperative myocardial protection, and provides excellent postoperative function in patients undergoing elective CABG.

Methemoglobinemia from intravenous nitroglycerin: a word of caution

The dose of intravenously administered nitroglycerin (IV NTG) used to control ischemic chest pain usually is limited by hypotension from decreased preload. Herein we describe 2 patients who tolerated IV NTG without hemodynamic compromise but in whom severe impairment of blood oxygen content developed from methemoglobinemia noted during coronary bypass surgery. Methemoglobinemia must be suspected if chocolate-brown blood is encountered despite a normal arterial oxygen tension and calculated oxygen saturation. Before a methemoglobin level is available, the extent of hypoxemia can be determined by an oximetric oxygen saturation and therapy begun with intravenous administration of methylene blue. These case reports focus attention on the potential deleterious effects of undetected hypoxemia from methemoglobinemia in patients being stabilized with high-dose IV NTG for urgent cardiac surgery.