Coronary vasospasm complicating PTCA

Abrupt vessel closure: changing importance, management, and consequences

Percutaneous coronary interventions have been performed for 20 years. Despite the success and progress of these interventions, abrupt vessel closure has been a dramatic adverse event of coronary interventions. Closure has frequently led to the major complications of death, myocardial infarction, and emergency coronary artery bypass. Because of the fear of this adverse event and its subsequent complications, the applicability of coronary interventions is sometimes limited. The pathologic characteristics of abrupt vessel closure have been recognized as predominantly caused by dissection, with vessel recoil and thrombus formation playing important secondary roles. The recognition of the lesions at risk for abrupt vessel closure has led to a strategy of lesion-specific device therapy to reduce complications. Similarly the role of antiplatelet and antithrombotic therapies have reduced complications. The earliest methods of dealing with abrupt closure was emergency coronary artery bypass surgery with significant rates of morbidity and mortality. With the advent of second-generation devices and techniques, particularly stents, the management of abrupt vessel closure has been simplified and alternatives to emergency coronary bypass are more available. This article will review the history and current status of the prevention and management of abrupt vessel closure and demonstrate that anticipation and management of this complication have been facilitated with reduction of subsequent complications and increased applicability of coronary interventions.

Potentiation of the vasospastic response to angioplasty by pretreatment with fluoxetine. A study in the atherosclerotic rabbit

There is evidence that angioplasty-induced vasospasm is mediated by serotonin (5-hydroxytryptamine [5-HT]) release from platelets. We tested the hypothesis that pretreatment of the atherosclerotic rabbit with fluoxetine, a platelet-uptake inhibitor of 5-HT, would reduce vasospasm after balloon angioplasty. Short-term administration of fluoxetine reduced platelet 5-HT uptake to 4% of baseline. Daily administration of fluoxetine for 7 days reduced whole-blood 5-HT levels to 28% of baseline. Thus, fluoxetine inhibited platelet 5-HT uptake in this model as predicted. Contrary to our expectations and despite the substantial reduction in whole-blood 5-HT levels, pretreatment with fluoxetine for 1 week resulted in augmentation of angioplasty-induced vasospasm in atherosclerotic rabbits. Intraperitoneal administration of fluoxetine produced vasoconstriction in normal rabbits that was augmented by 5-HT and not reversed with LY53857, a specific serotonin receptor antagonist. We postulate that this new observation is probably a result of the inhibition of the clearance mechanism for serotonin, with resultant enhancement of the effect of serotonin released by the activated platelets that are deposited on the vessel wall surface at the time of angioplasty. A direct effect of fluoxetine on serotonergic receptors is a second possible mechanism for the observed effect.

Vascular reactivity after balloon angioplasty in an atherosclerotic rabbit

Alterations in vessel wall reactivity (VR) at or adjacent to the dilation site after balloon angioplasty (BA) may vary according to the inflation protocol and the time after angioplasty and may influence outcome. In 64 atherosclerotic rabbit femoral arteries, we evaluated VR after BA with intravenous ergonovine (ERGO) (40 micrograms/min for 5 minutes) and intra-arterial nitroglycerin (NTG) (2,500 micrograms single bolus) 24-72 hours and 28 days after BA. Comparisons were made with atherosclerotic, nonangioplastied, age-matched controls. BA was standardized to three 1-minute inflations, each 1 minute apart. For each balloon size, 2.5- (appropriate size) or 3.0-mm (oversized) vessels were allocated to either 5 or 10 atm inflation pressure. For the analysis, four groups were compared: Group 1, 3.0/5; group 2, 3.0/10; group 3, 2.5/5, and group 4, 2.5 mm/10 atm. Angiographic diameters were measured at, proximal, and distal to the lesion at baseline, 10 minutes after ERGO, and 5 minutes after NTG. Angiograms were measured with electronic calipers by two blinded observers. All segments of control vessels vasoconstricted to ERGO and vasodilated to NTG (p less than 0.05 versus baseline), indicating a normal response. At 24-72 hours after dilatation, the angioplasty sites for all inflation pressure/balloon size combinations were not responsive to either ERGO or NTG. All segments distal to the dilatation sites vasoconstricted to ERGO and dilated to NTG (p less than 0.05 versus baseline), indicating a normal response. Proximal segments of vessels dilated with a 2.5-mm balloon (appropriate size) responded positively to both stimuli (p less than 0.05). Those vessels dilated with a large balloon (3.0 mm) were nonreactive in the segment proximal to the angioplasty site. Twenty-eight days later angioplasty sites dilated with a 2.5-mm balloon (appropriately sized) regained reactivity; however, segments dilated with a large balloon (3.0 mm) remained unresponsive. All proximal segments, including those from vessels dilated with a large balloon, reacted positively. All distal segments reacted appropriately. Restenosis rates were not different between the over- and appropriately sized balloon groups. These data demonstrate that immediately after angioplasty, vessels lose reactivity at the dilatation site. Those vessels dilated with the smaller-size balloon (2.5 mm) regained reactivity. For large balloons, reactivity is not regained at 28 days. For segments proximal to the site of dilatation, transient loss of reactivity is seen only when a large balloon is used. Thus, acute closure originating at the site of dilatation is not a result of spasm.(ABSTRACT TRUNCATED AT 400 WORDS)

Management of coronary occlusion during angioplasty: stabilization using a guide wire

During percutaneous transluminal coronary angioplasty of the left anterior descending artery in two patients, although the artery could be initially dilated, the vessel would not remain patent despite numerous redilations and pharmacological maneuvers. A third patient developed total occlusion of the right coronary artery during diagnostic catheterization. In these patients, the presence of a guide wire across the occlusion provided patency and stability. With the guide wire in place, the patients were taken to the operating room without further chest pain or evidence of ischemia.

Dose-related effects of intracoronary nitroglycerin on coronary hyperemia in patients with coronary artery disease

Although intracoronary nitroglycerin (NTG) is frequently required during percutaneous transluminal coronary angioplasty or thrombolysis, the dose-related hemodynamic effects and the extent to which intracoronary NTG--induced coronary hyperemia is limited in patients with coronary artery disease have not been defined. Therefore, we studied 19 patients with coronary artery disease (nine with no or minimal luminal narrowing of the left anterior descending coronary artery [group 1] and 10 with significant left anterior descending coronary stenosis [group 2]; mean arterial pressure and thermodilution coronary sinus and great cardiac vein blood flow were measured during bolus administrations of 50, 200, and 300 micrograms of intracoronary NTG. During the NTG-induced hyperemia, mean arterial pressure decreased 0%, 4% (both p = NS), and 6% (p less than 0.05) after 50, 200, and 300 micrograms doses, respectively. heart rate did not change. Global coronary hyperemia was greatest for 200 micrograms with coronary blood flow increasing (74 +/- 32% in group 1 and 53 +/- 25% for group 2) but was significantly different from 50 micrograms only in group 2 patients. Moreover, the regional coronary blood flow responses were attenuated in group 2 compared to group 1 for 50 micrograms, 18 +/- 13% vs 38 +/- 18%, and for 200 micrograms, 35 +/- 15% vs 72 +/- 34% (both p less than 0.05), with the reduction of regional coronary resistance in group 2 attenuated for all three doses of intracoronary NTG. The 300 micrograms dose did not provide further augmentation of either global or regional coronary blood flow or greater reduction in coronary resistance.(ABSTRACT TRUNCATED AT 250 WORDS)