James M. Perry

Demonstration of myocardial reperfusion injury in humans: Results of a pilot study utilizing acute coronary angioplasty with perfluorochemical in anterior myocardial infarction☆

Reperfusion may limit the amount of potentially salvageable myocardium through the introduction of cellular elements into previously ischemic but viable myocardium (reperfusion injury). It has been demonstrated that intracoronary infusion of a 20% intravascular perfluorochemical emulsion (Fluosol) significantly reduces infarct size and results in improved left ventricular function in the canine model. This pilot study was performed to explore the existence of myocardial reperfusion injury in humans. Utilizing Fluosol as a probe in conjunction with emergency coronary angioplasty, 26 patients presenting within 4 h with a first anterior myocardial infarction were randomized to emergency angioplasty or angioplasty followed by a 30-min intracoronary infusion of Fluosol at 40 ml/min. Global and regional ventricular function were assessed immediately and a mean of 12 days after successful angioplasty with contrast ventriculography. Infarct size was semiquantitated with thallium-201 single-photon emission computed tomography (SPECT) images before discharge. Twelve patients (six undergoing angioplasty alone, six treated with angioplasty and Fluosol) had an occluded infarct-related vessel (Thrombolysis in Myocardial Infarction [TIMI] grade 0 to 1) at the time of emergency catheterization and were included in the final analysis. At 12 days after successful angioplasty, the improvement in regional ventricular function was greater in patients receiving adjunctive therapy with intracoronary Fluosol versus those undergoing angioplasty alone utilizing both the radial shortening and centerline method, respectively (23 +/- 3.1% vs. 8 +/- 2.3%, p less than 0.02; and -1.6 +/- 0.4 vs. -2.9 +/- 0.2 SD/chord, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Determinants of left ventricular aneurysm formation after anterior myocardial infarction: a clinical and angiographic study.

To determine factors involved in left ventricular aneurysm formation after transmural anterior myocardial infarction, 79 patients with a first myocardial infarction who underwent cardiac catheterization within 6 months of infarction were evaluated. Patients who had received thrombolytic therapy were excluded. Patients were divided into four groups depending on the status of the left anterior descending artery and the presence or absence of a left ventricular aneurysm: Group I (n = 25): aneurysm with occluded left anterior descending artery; Group II (n = 27): no aneurysm and occluded left anterior descending artery; Group III (n = 23): no aneurysm and patent left anterior descending artery; and Group IV (n = 4): aneurysm with patent left anterior descending artery. Single vessel disease was more common in Group I (aneurysm) compared with Groups II and III (no aneurysm) (chi 2(4) = 12.8; probability value equal to 0.012). Collateral blood supply in the presence of an occluded left anterior descending artery was significantly less in Group I (aneurysm) compared with Group II (no aneurysm) (0.9 versus 2.4, p less than 0.001). The extent of coronary artery disease and collateral blood supply in Groups I and II were directly related (p = 0.012). Neither age, sex nor risk factors for coronary disease correlated with aneurysm formation. At a mean follow-up of 48 months, no differences were observed in the incidence of recurrent angina, new myocardial infarction, embolic events or sudden death. More patients in Group II underwent coronary artery bypass surgery. Total occlusion of the left anterior descending artery in association with inherent poor collateral blood supply is a significant determinant of aneurysm formation after anterior myocardial infarction. Multivessel disease with either good collateral circulation or a patent left anterior descending artery is uncommonly associated with the development of left ventricular aneurysm.

Lead Extraction in Young Patients With and Without Congenital Heart Disease Using the Subclavian Approach

Pacemaker lead removal using interlocking stylets and dilator sheaths has greatly reduced the need for major surgical intervention when lead extraction is required. Previous reports have shown the utility of this method in older patients, most of whom have anatomically normal hearts. The purpose of this study is to report the results of this technique in young patients with and with‐out congenital heart disease. There were 13 patients (M:F = 7:6) aged 9–26 years (median 13). Congenital heart disease was present in 8 of 13 patients. A total of 17 leads required removal; they had been implanted for 54 ± 24 months (range 19–94). Leads were removed from the left subclavian vein (13) or right subclavian vein (4) only. Seventeen of 18 leads were completely removed and one partially retained in the left subclavian vein. New leads were implanted from the same vein in 11 of 13 patients. Interlocking stylets and metal or flexible dilator sheaths were used in all cases except two. There was one surgical complication: a late wound dehiscence, which was easily managed. No patient required a transfusion, and there was no structural damage noted in any patient on the postoperative echocardiogram. We conclude that lead removal using interlocking stylets and dilator sheaths from the subclavian approach is an effective technique that can be used in young patients, including those with congenital heart disease.

Inotropic effects of tolbutamide in man

The hemodynamic responses of normal subjects to intravenous injections of tolbutamide, 250 mg., and 1,000 mg., were assessed by measurements of serial systolic time intervals. Analysis of results, compared to saline control, revealed evidence of minor inotropic effects during the period five to 10 minutes after infusion. Small but statistically significant (p less than 0.05) decreases in pre-ejection phase and electromechanical systole were noted. The time response of these changes did not correlate with dose of blood level of tolbutamide, and appeared to coincide with peak insulin levels. No inotropic or chronotropic effects were seen during the first four minutes after infusion, suggesting that the myocardial adenyl cyclase-stimulating properties of the drug, previously demonstrated in vitro, are not significant in intact man. The minor late inotropic effects are of doubtful clinical significance, and cannot be invoked to explain the reported increased cardiovascular mortality of patients treated with tolbutamide.

Correlation of saphenous vein bypass graft angiograms with histologic changes at necropsy

Previous studies of saphenous vein (SV) bypass grafts have been either angiographic or morphologic, and few have correlated angiograms with histology. Nine necropsy patients who had received 21 SV implants 12 to 120 months (mean 67 +/- 42) before death were studied. All patients had severe coronary artery disease. Three types of histologic changes were found: atherosclerosis in 9 grafts, fibrointimal proliferation in 8 and total occlusion with fibrosis in 4. All patients had premortem angiograms 0 to 3 months (mean 0.7 +/- 1.1) before death. In 14 of 21 grafts, premortem angiograms accurately reflected the postmortem findings. In 7 grafts, the premortem angiograms either overestimated (4 grafts) or underestimated (3 grafts) the extent of luminal narrowing. Six of the 7 SV implants incorrectly assessed by angiography had fibrointimal proliferation and 1 had atherosclerosis. The presence of smooth muscle in SV implants with fibrointimal proliferation may be a mechanism of spasm or relaxation during angiography, which could cause errors in estimating the degree of stenosis. Nitrates or calcium antagonists may be useful in both assessing the degree of underlying vasomotion in SV grafts and as a therapeutic modality.

Evaluation of a prolonged infusion of recombinant tissue-type plasminogen activator (Duteplase) in preventing reocclusion following successful thrombolysis in acute myocardial infarction☆

The hypothesis that an infusion of recombinant tissue-type plasminogen activator (rt-PA) maintained for up to 24 hours could prevent reocclusion after early coronary patency had been established was evaluated in patients with acute myocardial infarction. The rt-PA studied was an investigational double chain rt-PA (Duteplase, Burroughs Wellcome Co.), administered according to body weight. Coronary patency was documented in 139 of 213 patients who had 90-minute angiograms recorded after an initial lytic dose of rt-PA. In these responders a further 90-minute infusion at one third the initial lytic dose was given before assignment to 1 of 4 maintenance dose rates (0.012, 0.024, 0.036, 0.048 MIU/kg/hour) which were continued for the subsequent 9 to 21 hours. The principal end point was the status of the infarct-related coronary artery 12 to 24 hours after the start of therapy, and before termination of rt-PA, in patients with initially patent vessels at 90 minutes. Of the 103 responders with repeat angiograms after a 9 to 21 hour maintenance infusion of rt-PA, a total of 17 (16.5%) patients reoccluded across all doses administered. There was no significant relationship between the maintenance dose rate and the incidence of reocclusion. However, there was strong association between total dose of rt-PA administered and the incidence (16%) of serious or life-threatening bleeding exclusive of surgery. Other factors associated with serious bleeding included low body weight, female gender, and total duration of rt-PA infusion. Reocclusion was independent of the 90-minute Thrombolysis in Myocardial Infarction trial perfusion grade and diameter of infarct vessel. Rethrombosis after establishment of early patency after rt-PA remains a significant problem that is unaffected by sustained rt-PA infusion in doses that can be tolerated.

Myocardial infarct artery patency and reocclusion rates after treatment with duteplase at the dose used in the International Study of Infarct Survival-3

Duteplase, 98% double-chain recombinant tissue-type plasminogen activator, was administered intravenously in 488 patients with acute myocardial infarction in a multicenter, open, safety and patency study. Duteplase dosing was based on body weight. Duteplase was administered as a bolus of 0.04 MIU/kg of thrombolytic activity followed by 0.36 MIU/kg over 1 hour and 0.067 MIU/kg/hour for 3 additional hours. The patency rate of the infarct-related artery at 90 minutes was 69% (330 of 478). The reocclusion rate at 3 to 48 hours was 6% (18 of 301). Reinfarction occurred in 7.6% of patients (37 of 488), but 12 reinfarctions occurred after coronary angioplasty. Serious bleeding occurred in 7.6% of patients (37 of 488), predominantly at the catheterization entry site. There were 3 instances of central nervous system bleeding, 1 fatal. Fibrinogen levels declined to 83% of baseline at 24 hours. Weight-based dosing may explain the low incidence of serious bleeding in this study. The in-hospital mortality was 6.6% (32 of 488). This study documents that the dose of duteplase used in the International Study of Infarct Survival-3 results in a 90-minute coronary artery patency rate and safety profile comparable to those reported in published studies on the approved dose of alteplase.

Detection of left atrial thrombi

Abstract Scintillation scanning to detect atrial thrombi after intravenous administration of 131 I labeled antibodies to human fibrinogen was performed on 30 patients who had mitral valve surgery under cardiopulmonary bypass. Twenty-six patients had negative scans and at operation no thrombus was found in 25. Of the 4 patients with positive scans, 3 had left atrial thrombi at surgery and 1 had a highly calcified valve. 131 I determinations of blood, surgically removed cardiac tissue, and thrombi demonstrated that the thrombi could have as much as 25 times more 131 I than that in an equivalent amount of blood. Little 131 I accumulation was found in organized, avascular portions of the thrombus or atrial appendage, mitral valve, and tricuspid valve. Because of the high concentration of 131 I in the thrombus compared to that in the cardiac tissue and blood, this procedure seems promising as a means of detecting atrial thrombi with little discomfort to the patient. It is suggested that the use of an antiserum to rabbit gamma globulin to remove immunologically the major portion of the blood-borne 131 I rabbit antiserum to human fibrinogen may appreciably increase the ratio of thrombus to blood and this would decrease the possibility of falsenegative scans and increase the resolution of positive scans.

Experimental Results Of Image Registration In Digital Subtraction Angiography With An In Vivo Phantom

Motion artifacts caused by moving anatomy degrade images acquired by means of digital subtraction angiography. It is in principle possible to remove these artifacts through image registration by means of geometrical transformations of properly calibrated images, but there are known difficulties with this approach. In this paper we consider two of these difficulties, the presence of x-ray scatter and, more significantly, the inherent absence of sufficient information to identify correct transformations. We perform experiments using a novel phantom to illustrate these difficulties. The phantom is a balloon that is inflated within the lumen of a coronary artery during percutaneous transluminal angioplasty. We employ two registration techniques, a previously described technique to compensate for gross, simple motion, and a novel one to compensate for smaller, more intricate motion.