Biomedical subjects
Publications and source records attributed to J D Garnic.
During PTCA immediate decisions often must be made on the basis of a less than optimum data set. We present a combination of factors which produce an incorrect perception of a coronary artery dissection. This potential must be understood by the interventionalist to avoid misdiagnosis and inappropriate therapeutic maneuvers.
The effects on the evolution of canine myocardial infarction (MI) of the lymphagogues hyaluronidase (hyaluronate glucanohydrolase) (known to reduce the size of MIs) and calcium dobesilate (calcium, 2,5-dihydroxybenzenesulfonate, CLS 2210) were compared in a coded, placebo-controlled study in 48 dogs, during the first 24 h after coronary occlusion. MI was induced by embolization of the anterior descending branch of the left coronary artery. The animals were given either a placebo, CLS 2210, or hyaluronidase by intravenous infusion begun immediately after embolization and continued for 24h. The volume of myocardial tissue at risk was evaluated at 2 and 24 h by ungated computed tomography (CT), and after necropsy by staining myocardial sections with triphenyl tetrazolium chloride (TTC). Electrocardiography and estimation of serum creatine kinase (CK) activity were also performed. In the 25 animals that survived 24 h, the results of all tests showed that there was less myocardial damage in the animals treated with the two lymphagogues than in those treated with placebo, and less damage with CLS 2210 than with hyaluronidase. The good correlation between the volume of ischemic tissue as assessed by CT in vivo and as assessed by TTC staining after necropsy (r = 0.959) confirms that the CT perfusion phase defect accurately reflects the volume of tissue at risk during the evolution of MI. This study has shown that CLS 2210 is at least as effective as hyaluronidase in reducing myocardial damage due to coronary artery occlusion in dogs.
Cardiac injuries following nonpenetrating chest trauma have been reported. These include cardiac arrhythmias, septal damage, valve damage, coronary fistula, coronary artery damage, ventricular aneurysm, cardiac rupture, and myocardial infarction. Myocardial infarction as a complication of chest trauma has been reported in very few cases. In this report the authors describe a patient who developed anterior wall myocardial infarction secondary to a blunt chest trauma.
A tapered teflon dilator has been applied to 12 cases of percutaneous transluminal coronary angioplasty (PTCA). The technique was first used to predilate stenoses that could not initially be crossed with low profile over the wire PTCA balloons. In the first five cases, three angioplasties that would have been failures were converted to successes by this method. The dilator was used in place of a balloon catheter as an initial step to assess the ability of a guidewire to cross a lesion to reduce cost in five additional cases. Modification of an existing family of peripheral vascular dilators is described. The method of application of this technique to PTCA is outlined.
A technique using a tapered teflon dilator was applied to percutaneous transluminal coronary angioplasty (PCTA). Seven of 10 cases were successfully dilated by using this technique. These lesions could not be dilated in the usual manner using standard PTCA balloons. This technique converted 7 of 10 failed procedures into technical successes and is the basis of this report.
To test the reliability of conventional selective pulmonary arteriography in the diagnosis of pulmonary embolism, three angiographers reviewed the arteriograms of a series of 60 patients retrospectively, independently, and without benefit of additional data. Pulmonary arteriograms had been interpreted as positive for pulmonary embolism in 25 of these patients during their hospitalizations. Angiographers A, B, and C judged the arteriograms of 24, 29, and 25 patients, respectively, as positive for pulmonary embolism. Mean interobserver agreement was 86%. Interobserver agreement was not associated significantly with the quality of the arteriogram or with selective injection of a lobar vs a pulmonary artery, but was associated strongly with the magnitude of thromboembolism. All angiographers agreed that the arteriograms were positive in 18 cases of pulmonary embolism graded as massive, lobar, or segmental, but agreed in only two of 15 cases graded as subsegmental. We conclude that conventional selective pulmonary arteriography is reliable in the detection of embolus in segmental or larger pulmonary arteries. Observer disagreement becomes considerable for embolus limited to subsegmental pulmonary arteries, indicating that emboli of this size are at the resolution limit of the technique.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A difficult problem in coronary arteriography is the assessment of the hemodynamic significance of stenoses that appear angiographically to be of only moderate severity (25 to 75% diameter narrowing). This is particularly important in patients who may be candidates for invasive therapy, such as percutaneous transluminal coronary angioplasty (PTCA) or coronary bypass surgery. To determine the significance of such lesions, we measured transstenotic coronary pressure gradients in 15 patients with angiographically moderate stenoses. For comparison, similar measurements were made in 17 patients with severe stenoses (more than 75% diameter narrowing) being considered for PTCA. The transstenotic pressure gradients were measured with a 2.0Fr polyvinyl chloride catheter cleared of microbubbles of air by flushing with carbon dioxide and degassed saline solution and attached to a low-volume displacement transducer for optimal frequency response. Mean transstenotic pressure gradients greater than 10 mm Hg at rest or more than 20 mm Hg under conditions of high coronary blood flow, as induced by Renografin 76, appeared to be associated with objective evidence of myocardial ischemia and symptomatic relief from PTCA. Smaller pressure gradients occurred in patients whose symptoms probably were not ischemic in nature. Transstenotic pressure gradient determination performed at the time of diagnostic catheterization may provide assistance in clinical decision-making in selected patients with angiographically moderate stenoses.
Major improvements in the resolving power of computed tomography and ultrasound over the last decade have greatly improved the preoperative evaluation of abdominal masses. Angiography is, however, still often required for vascular mapping and assistance in the differential diagnosis. Although the site of origin of an avascular, intrasplenic mass may be the spleen, our experience and review of the literature indicates that such primary or secondary splenic masses are relatively rare. A primary pancreatic mass often a pseudocyst is a more frequent cause and should figure prominently in the differential diagnosis.
Several vasodilators, including acetylcholine, are capable of inducing maximal renal vasodilatation when infused into the renal artery. Despite substantial interest in the renal vascular response to calcium channel blocking agents, there has been no systematic comparison of any of these agents to an index vasodilator, such as acetylcholine. We compared the renal vascular angiographic response to acetylcholine and diltiazem, infused into the renal artery in graded dosage, in 14 dogs. In eight of the dogs renal blood flow was measured with an electromagnetic flowmeter. At peak, the acetylcholine-induced increase in renal blood flow (155 +/- 25 to 309 +/- 55 ml/min) slightly exceeded that induced by diltiazem (143 +/- 13 to 257 +/- 58 ml/min). A close correlation was found between the maximal blood flow increase induced by acetylcholine and by diltiazem (R = .95). Dilatation of the intrarenal arterial tree evident on the renal arteriogram was substantially less striking with diltiazem than with acetylcholine in these eight dogs. To ascertain the possible contributing role of the surgery required for blood flow measurement, the two agents were assessed in six additional dogs without blood flow measurement. In these six dogs diltiazem and acetylcholine induced essentially identical degrees of renal arterial vasodilatation. It is concluded that diltiazem, the calcium channel blocking agent, produces near maximal renal vasodilatation at the arteriolar level and that responses of more proximal elements of the renal arterial tree, visible during renal arteriography, are sensitive to the conditions of the experiment.
Biplane pulmonary cineangiograms utilizing a short cine pulse width and automatic brightness control were performed in 47 patients during normal respiration. The diagnostic quality of the arteriograms was categorized as good in 33 patients, fair in 12 patients, and poor in two patients. Of the 18 patients in whom pulmonary emboli were identified, cineangiography displayed certain diagnostic features to advantage, including motion of emboli in ten and respiratory scissoring of vessels overcoming vascular superimposition in three. Optimized pulmonary cineangiography is an acceptable alternative to serial film pulmonary angiography for the diagnosis of pulmonary embolism.
The original Gruentzig coaxial catheter system for percutaneous transluminal coronary angioplasty (PTCA) utilized a blunt, closed-end, inner balloon catheter with a short guide wire attached to its tip. Options for safely crossing severe stenoses with this large, nonmaneuverable catheter were limited. More recently, over-the-wire systems have been developed in which the lesion initially is crossed with a small-caliber floppy or steerable guide wire, then by the balloon catheter advanced over the wire. Technical success was achieved in 78 of our first 100 PTCAs with this system. Significant cardiac complications occurred in ten patients, seven of whom required emergency coronary bypass surgery. A recently published survey of all PTCA techniques reported a technical success rate of 62%. Our higher success rate may be attributed to certain advantages of the over-the-wire system, which are discussed in detail. A learning curve is associated with this procedure: our success rate was 65% in the first 20 cases but 81% thereafter. These results can be considered typical of those expected at hospitals now beginning PTCA programs with advanced over-the-wire technology.
Previously published papers on percutaneous transluminal angioplasty (PTA) have emphasized results rather than techniques. This review deals with equipment choices, technical aspects and pitfalls observed during the first 200 PTAs at the Brigham and Women's Hospital. Specific topics discussed include: (1) catheters kept in stock in the laboratory, (2) choice of approach and entry into the artery, (3) techniques for crossing stenoses, (4) dilatation of the lesion, (5) drugs used during the procedure, and (6) proper performance and interpretation of the postangioplasty arteriogram.
Explore the source record for details and available documents.
The increasing role of percutaneous transluminal angioplasty in the therapy of renal artery stenosis has, in turn, emphasized the need to optimize imaging of the entire length of the main renal artery and its major branches. The usual angiographic positioning techniques for anteroposterior and oblique views may not be adequate to define the precise location and extent of a stenosis. The authors combine oblique projections with sagittal angulation of the x-ray tube to augment the standard imaging methods for selective renal arteriography.
Interventional angiographic techniques are of increasing importance in the management of arteriosclerosis and its complications. Two areas of particular interest are the treatment of focal arterial stenoses by percutaneous transluminal angioplasty and the treatment of arterial thromboemboli with selective infusion of thrombolytic agents. The administration of multiple drugs, in various combinations, is a critical factor in the success of these interventions. To effectively use this new pharmacoangiography, it is important to understand both the pathophysiology of the atherosclerotic or thrombotic process being treated and the actions of the drugs used. Preserving the effect of angioplasty relies on preventing thrombus formation and preventing recurrence of the atherosclerotic obstruction. Heparin during the procedure is clearly useful for the former, and aspirin in small doses and other antiplatelet medications are indicated for the latter. The precise utility of long-term anticoagulation, of low molecular weight dextran, and of various antiplatelet regimens remains to be proven. The theoretical importance of these medications in improving long-term patency rests on the effects they have on platelet and vessel wall prostaglandins, on intimal smooth muscle cell proliferation, and on the thrombogenicity of injured arterial intima. Fibrinolytic therapy, with streptokinase and urokinase, has been used for many years. Selective intraarterial use, however, is a new and promising application. Intracoronary streptokinase infusion during acute myocardial ischemia appears to prevent or limit infarction in certain patients. Peripheral use for acute arterial occlusion, either in native vessels or in grafts, is an area of great promise. Key considerations are thrombus age, size, and location, and the status of the arterial flow proximal and distal to the obstruction.
Explore the source record for details and available documents.