Neil A. Buchbinder

Intracoronary thrombolysis in evolving myocardial infarction.

Abstract After experimental studies in dogs confirmed the feasibility and safety of rapid intracoronary thrombolysis by local infusion of Thrombolysin (streptokinase and plasmin), intracoronary thrombolysis was attempted in 20 patients with evolving myocardial infarction who were hospitalized within 3 hours from the onset of symptoms during the day and within 2 hours at night. Thrombolysin was infused in the immediate vicinity of the site of coronary occlusion using a 0.85 mm outer diameter catheter advanced through the lumen of the Judkins catheter. Reperfusion was achieved in four patients after an average of 43 minutes of Thrombolysin infusion at a rate of 2000 IU/min and in 15 patients after an average of 21 minutes of Thrombolysin infusion at a rate of 4000 IU/min. The failure to open the artery in one patient may have been caused by our inability to advance the infusion catheter close to the site of occlusion. Rethrombosis occurred in one patient 8 days after reperfusion and 2 days after discontinuation of anticoagulants because of a history of chronic alcoholism. Wall motion and perfusion studies showed improvement following reperfjsion. Patency of the artery was achieved an average of 4 hours after the onset of symptoms. The need for earlier reperfusion is emphasized.

Left-sided valvular active infective endocarditis. A study of forty-five necropsy patients

Abstract Clinical and anatomic features are described in forty-five necropsy patients with left-sided valvular active infective endocarditis. Vegetations in 53 per cent of the patients involved previously anatomically normal valves, and 76 per cent of all patients had previously functionally normal valves. Predisposing factors allowing entrance of virulent or unusual organisms or alterations of host defense mechanisms appear to account for the frequency of infective endocarditis on normal valves. Valvular dysfunction resulting from infective endocarditis occurred in at least 59 per cent and possibly as high as 74 per cent of the forty-five patients causing congestive heart failure in all. Myocardial lesions were present in 87 per cent of the thirty-eight patients in whom multiple histologic sections were examined, but in none did heart failure appear to result from these lesions. Papillary muscle necrosis was present in 58 per cent, but in none did it appear to cause mitral regurgitation. Congestive heart failure could not be attributed in any patient to myocardial lesions. Pericarditis occurred in eight patients (20 per cent), and in each a site of direct extension of the inflammation into the pericardium was apparent. Ring abscesses occurred in twelve of thirty-one patients with aortic valve vegetations and in none of twenty-six with mitral valve vegetations. Ring abscesses indicate severe destruction of valvular cusps and severe valvular dysfunction.

Right-sided valvular infective endocarditis: A clinicopathologic study of twelve necropsy patients

Abstract Clinical and necropsy features are described in twelve patients with infective endocarditis involving right-sided cardiac valves. In six patients infective endocarditis was limited to the tricuspid valve; in the other six vegetations also were present on one left-sided cardiac valve, but in only one of them was the infective endocarditis definitely primary on the left side of the heart. The tricuspid valve was the site of infective endocarditis in eleven patients and the pulmonic valve in one. The organisms responsible for the infective endocarditis were Staphylococcus aureus in six patients, Diplococcus pneumoniae in four, alpha Streptococcus in one and Aspergillus flavus in one. Five patients were alcoholics, four were heroin addicts, two had blood dyscrasias, and one had congenital cardiac disease (ventricular septal defect). The infective endocarditis in each of the nine patients with alcoholism or heroin addiction and in the one with congenital heart disease was primary in the heart; in the remaining two patients, it was secondary to generalized infection affecting many body organs. Acute pneumonia was a dominant clinical feature in ten of the twelve patients and appeared to be secondary to dislodgment of material from the right-sided cardiac vegetations. Six patients also had acute meningitis. Although the vegetations caused considerable damage to the right-sided cardiac valves, evidence of cardiac dysfunction was either absent or attributable to acute cor pulmonale secondary to the acute pneumonia. Attention is called to the common tetrad of chronic alcoholism, acute pneumonia, acute meningitis and infective endocarditis. In nine of the twelve patients the right-sided vegetations did not extend to involve the basal attachments of the leaflets to the annuli. Thus, in these nine patients total excision of the valve leaflets would have eradicated their valvular endocarditis.

Myocardial salvage by intracoronary thrombolysis in evolving acute myocardial infarction: Evaluation using intracoronary injection of thallium-201

Abstract Immediate objective assessment of viabillty of reperfused myocardium following intracoronary (IC) thrombolysis by evaluation of ventricular function may be limited due to delay in restoration of function. Thus we assessed myocardial uptake of thallium-201 (TI-201) following IC injection postreperfusion as an index of myocardial salvage in 12 experimental dogs and in five patients with evolving acute myocardial infarction (AMI). In seven dogs with mean of 313 minutes of experimental coronary occlusion, immediate postreperfusion IC TI-201 images revealed absence of myocardial uptake in prevlously occluded zones. These TI-201 defects correlated with presence of necrosis as demonstrated by histochemical staining with triphenyl-tetrazolium chloride (TTC). In contrast, in five dogs with mean of 37 minutes of coronary occlusion, reperfused myocardium showed normal TI-201 uptake following its IC injection; this normal TI-201 uptake pattern correlated with absence of necrosis by TTC technique in all five dogs. In five patients with evolving AMI, control TI-201 images obtained following IV injection prior to IC thrombolysis showed myocardial perfusion defects corresponding to distribution of the occluded vessel. Following reperfusion, 30 to 50 mCi of TI-201 was injected into the reopened coronary artery. In two patients with mean symptom onset of reperfusion time of 2 1 2 hours , immediate postreperfusion IC TI-201 images demonstrated normal or improved TI-201 uptake in reperfused myocardium. By radionuclide ventriculography, segmental wall motion remained abnormal in the reperfused regions 6 hours postreperfusion and showed improvement by the time of 10-day study. In the remaining three patients with symptom onset to reperfusion time of 5 hours, immediate postreperfusion IC TI-201 images did not show improvement, correlating with persistent wall motion abnormalities 10 days postreperfusion. In all five patients, repeat 10-day IV TI-201 images were unchanged from the immediate postreperfusion IC TI-201 images. We conclude that (1) prereperfusion TI-201 imaging with repeat TI-201 injection into the reopened coronary artery appears to delineate the extent of myocardial salvage in both experimental and clinical studies and (2) this method of IC TI-201 imaging allows immediate assessment of myocardial viabillty which may facilltate decisions regarding the need for additional myocardial revascularization modalities.

Synchronized coronary venous retroperfusion for support and salvage of ischemic myocardium during elective and failed angioplasty

To determine the safety and efficacy of synchronized coronary venous retroperfusion during brief periods of ischemia, 30 patients undergoing angioplasty of the left anterior descending coronary artery were studied. Each patient underwent a minimum of two angioplasty balloon inflations. Alternate dilations were supported with retroperfusion; the unsupported inflations served as the control inflations. Synchronized retroperfusion was performed by pumping autologous femoral artery blood by means of an electrocardiogram-triggered retroperfusion pump into the great cardiac vein through a triple lumen 8.5F balloon-tipped retroperfusion catheter inserted percutaneously from the right internal jugular vein. Clinical symptoms, hemodynamics and two-dimensional echocardiographic wall motion abnormalities were analyzed. Retroperfusion was associated with a lower angina severity score (0.8 +/- 1 vs. 1.2 +/- 1) and delay in onset of angina (53 +/- 31 vs. 37 +/- 14 s; p less than 0.05) compared with the control inflations. The magnitude of ST segment change was 0.11 +/- 0.14 mV with retroperfusion and 0.16 +/- 0.17 mV without treatment (p less than 0.05). The severity of left ventricular wall motion abnormality was also significantly (p less than 0.01) reduced with retroperfusion compared with control (0.7 +/- 1.4 [hypokinesia] vs. -0.3 +/- 1.6 [dyskinesia]). There were no significant changes in hemodynamics, except in mean coronary venous pressure, which increased from 8 +/- 3 mm Hg at baseline to 13 +/- 6 mm Hg with retroperfusion. Four patients required prolonged retroperfusion for treatment of angioplasty-induced complications. The mean retroperfusion duration in these patients was 4 +/- 2 h (range 2 to 7). In the three patients who underwent emergency bypass surgery, the coronary sinus was directly visualized during surgery and found to be without significant injury. There were no major complications. Minor adverse effects were transient atrial fibrillation (n = 2), jugular venous catheter insertion site hematomas (n = 4) and atrial wall staining (n = 1), all of which subsided spontaneously. Thus, retroperfusion significantly reduced and delayed the onset of coronary angioplasty-induced myocardial ischemia and provided effective supportive therapy for failed and complicated angioplasty.

Does the presence and site of myocardial ischemia on perfusion scintigraphy predict the occurrence and site of future myocardial infarction in patients with stable coronary artery disease

In 47 patients who had undergone myocardial scintigraphy, reversible perfusion abnormality was detected in only 28 segments (60%) that were the site of future acute myocardial infarction.

Improved assessment of inferior segmental wall motion by the addition of a 70-degree left anterior oblique view in multiple gated equilibrium scintigraphy☆

Conventional anterior and 45-degree left anterior oblique (LAO) views are limited in the evaluation of inferior segmental wall motion by multiple gated equilibrium cardiac blood pool scintigraphy. This study evaluated the addition of a 70-degree LAO view by comparing scintigraphic and contrast ventriculography in 25 patients, of whom 17 demonstrated abnormal inferior wall motion. Abnormal inferior wall motion was correctly identified in only 10 of 17 patients in the anterior view, but in 16 of 17 patients in the 70-degree LAO view. The number of assessable inferior segments was improved from 58% in the anterior view to 98% in the 70-degree LAO view. When the inferior segments could be visualized in the anterior view, inferior wall motion was accurately assessed. The addition of the 70-degree LAO view aids in the multiple gated equilibrium scintigraphic detection of inferior wall motion abnormalities with a minor loss in specificity.

A Prospective, Nonrandomized, Open-Labeled Pilot Study Investigating the Use of Magnesium in Patients Undergoing Nonacute Percutaneous Coronary Intervention with Stent Implantation

Background: Magnesium has recently been shown to inhibit acute stent thrombosis in animal models. This study tested the feasibility of magnesium administration in patients undergoing nonacute percutaneous coronary intervention with stent implantation. Methods: Twenty-one patients undergoing nonemergent percutaneous coronary intervention were enrolled and received intravenous magnesium sulfate (2-g bolus over 20 minutes prepercutaneous coronary intervention, followed by 14 g over 12 hours infusion). Endpoints: safety outcomes-hypotension, bradycardia, bleeding complications and heart block within first 24 hours; angiographic outcomes-acute thrombotic occlusion and need for platelet glycoprotein Ilb/Illa inhibitor bailout; and clinical outcomes-death, myocardial infarction, recurrent ischemia, and need for urgent revascularization at 48 hours and 30 days. Results: No significant effects on heart rate or blood pressure, major bleeding complication, or new electrocardiographic changes were observed. Angiographic thrombus was visualized in two cases, and coronary artery dissection in one case poststent deployment. None of these cases required the use of glycoprotein inhibitors for bailout. Death, myocardial infarction, recurrent ischemia, and need for urgent revascularization were not observed. The serum magnesium level increased from 2.1 ± 0.3 mg/dL at baseline to 3.5 ± 0.8 mg/dL at the end of the infusion (P < .0001). Platelet activation was significantly inhibited at the end of the magnesium sulfate infusion. Conclusion: Intravenous magnesium sulfate has been demonstrated as a feasible and safe agent in patients undergoing nonacute percutaneous coronary intervention with stent implantation. A randomized clinical trial comparing magnesium with glycoprotein inhibitors during percutaneous coronary intervention is warranted.

Echocardiographic and pathologic features of explanted Hancock and Carpentier-Edwards bioprosthetic valves in the mitral position

Modes of failure of Hancock and Carpentier-Edwards (C-E) porcine bioprosthetic valves placed in the mitral position are not completely understood. We reviewed transesophageal echocardiographic (n = 19) and pathologic features of failed Hancock (n = 22) and C-E (n = 8) porcine mitral valves in 30 patients (mean age 70 +/- 13 years). Age at implantation (59 +/- 14 vs 58 +/-14 years, p = 0.9), time to implanted valve degeneration (13 +/- 5 vs 11 +/- 2 years, p = 0.3), and size of bioprosthesis (30 +/- 2 vs 31 +/- 2 mm, p = 0.14) of the implanted Hancock and C-E valves were similar. Anterior leaflet was flail in 15 versus flail posterior leaflet in 5 patients (p = 0.0004). Eccentric posterior mitral regurgitation jet was present in 12, eccentric anterior jet in 2, central jet in 2, and paravalvular jet in 3 patients. Stenosis of bioprosthesis was present in 1 1 Hancock versus 1 C-E valve (p = 0.06). Stent creep at any stent post was present in 14 Hancock versus no C-E valve (p = 0.0013). Large commissural dehiscence was present in 5 C-E versus 1 Hancock valve (p = 0.0006). Ring margin perforation was the most common perforation in Hancock valves (p <0.05, analysis of variance versus all other Hancock perforations). Dehiscence at the stent posts was the most common perforation in C-E valves (p <0.05 vs other C-E perforations, analysis of variance and p <0.001 versus Hancock valves). Thus, Hancock valves showed greater stenosis and stent creep, whereas C-E valves showed large dehiscences at the stent posts on explantation. The anterior leaflet degenerated most frequently in both valves. These findings suggest that the valve design may influence the mechanisms of porcine valve degeneration.

Assessment of the functional significance of coronary artery disease with atrial pacing and cardiokymography

Abstract Thirty-six patients were studied during the course of cardiac catheterization to assess the role of cardiokymography and atrial pacing in the functional evaluation of angiographic coronary arterial stenosis. Only 4 of 25 patients with greater than 50 percent diameter stenosis of at least one major vessel had 0.1 mv or greater S-T segment depression at a paced heart rate of 123 ± 25/min, and 2 of 11 normal patients revealed a similar response (P = not significant). In contrast, in 22 of 25 patients systolic outward motion developed as determined with cardiokymography during the same pacing period, whereas in only 1 of 11 normal patients a similar abnormality did develop (P These data are consistent with the view that regional wall motion abnormalities are highly sensitive and specific markers of ischemia and that such abnormalities may be detected noninvasively with cardiokymography. It is concluded that atrial pacing in conjunction with cardiokymography is applicable to the functional assessment of ischemic heart disease and may provide a means for objective evaluation of the significance of angiographically observed coronary stenosis.