Martyn R. Thomas

Inhibition of platelet activity by S-nitrosoglutathione during coronary angioplasty

Platelet activation is associated with acute vessel occlusion and chronic restenosis after percutaneous transluminal coronary angioplasty (PTCA). Organic nitrates, which act by releasing the vasodilator and anti-platelet agent nitric oxide (NO), have a predominantly vasodilator action and cause hypotension at doses required to inhibit platelet activation. S-nitrosoglutathione (GSNO) is an NO donor with a preferential action on platelets. We investigated platelet activation in patients undergoing PTCA and the effect of GSNO. Blood was sampled from the coronary sinus to measure platelet surface expression of P-selectin and glycoprotein IIb/IIIa as indices of platelet activation. In 7 control patients, PTCA caused a rise in platelet surface expression of P-selectin and glycoprotein IIb/IIIa, which was maximal 5 minutes after PTCA, indicating increased platelet activation despite treatment with aspirin, glyceryl trinitrate, and heparin. 6 patients received an intracoronary infusion of GSNO, starting 10 min before PTCA. GSNO significantly inhibited the PTCA-induced increase in platelet surface expression of P-selectin and glycoprotein IIb/IIIa without altering blood pressure. These findings show that platelets are activated following PTCA and that GSNO can prevent this activation.

Coronary artery perforation during percutaneous intervention: incidence and outcome

Objective: To examine the clinical outcome of percutaneous coronary intervention where the procedure was complicated by vessel perforation. Setting: Tertiary referral centre. Methods: The procedural records of 6245 patients undergoing coronary intervention were reviewed. In 52 patients (0.8%) the procedure was complicated by vessel perforation, ranging from wire exit to free flow of contrast into the pericardial space. The majority of lesions treated were complex (37% type B, 59% type C) and 9 of 52 (17%) were chronic occlusions. Ten patients (19%) received abciximab. Four underwent rotational atherectomy (8%). Results: In 28 of 52 patients (54%) the perforation was benign and managed conservatively without the development of haemodynamically significant sequelae. In 24 of 52 (46%) a significant pericardial effusion ensued requiring drainage. Of these 24 procedures 6 had involved the treatment of a chronic occlusion (25%). Eight of the 24 patients were referred for emergency bypass surgery (33%), 3 of whom died. Of the remaining 16 not referred for surgery, 3 died. Of the 10 procedures complicated by vessel perforation where abciximab had been administered, 9 (90%) led to pericardial tamponade. Latterly 2 vessel perforations were successfully treated by the deployment of a covered stent. Conclusions: Coronary artery perforation with sequelae during intervention is rare—26 of 6245 (0.4%). This complication was seen in the treatment of chronic occlusions, which are therefore not risk-free procedures. The development of pericardial tamponade carries a high mortality. While prompt surgical intervention may be life saving, expertise in the use of covered stents may provide a valuable rescue option for this serious complication. Caution should be exercised where coronary perforation occurs and abciximab has been used.

Cardiac troponin T and I and creatine kinase-MB as markers of myocardial injury and predictors of outcome following percutaneous coronary intervention

AIMS This study was performed to determine the most sensitive biochemical marker for the detection of cardiac myocyte damage potentially sustained during percutaneous coronary intervention (PCI) and to assess whether such a marker can be used to identify patients at increased risk of poor subsequent clinical outcome. METHODS AND RESULTS We studied 109 consecutive patients presenting with clinical stable and unstable angina and undergoing PCI at our institution. Blood was sampled for creatine kinase-MB (CK-MB), cardiac Troponin T (cTnT) and I (cTnI) immediately before and at 6, 14 and 24 h post-PCI. Five patients with raised cardiac markers pre-PCI were excluded from further analysis. The occurrence of major adverse cardiac events (MACE) was documented in-hospital, at 30 days and at long-term clinical follow up of up to 20 months. MACE occurred in 26/109 (24%) patients: death=1, QWMI=4, NQWMI=5, repeat PCI=16 (nine target vessel revascularisations and seven de-novo lesions), CABG=5. cTnI had the highest detection rate for myocardial damage, with 58 cTnI-positive patients, 38 cTnT-positive patients and 28 CK-MB-positive patients in the 24 h following PCI (Pearsons Chi square test, P<0.01). The type of interventional strategy per se was not significantly associated with post-procedural cardiac marker concentrations (Kruskal-Wallis ANOVA, P>0.05). There was a significant association between post-procedural cardiac marker concentrations of CK-MB, cTnT and cTnI and the occurrence of procedural angiographic complications (P=0.0003, 0.0002, 0.001, respectively). All three markers, at each sampling time point between 6 and 24 h post-PCI, showed a significant predictive relationship with MACE in-hospital and at long-term follow up (ROC curve AUC analysis, P<0.05). All three markers provided equally predictive information at each of the three post-procedural sampling time points between 6 and 24 h following PCI. All levels of cardiac marker elevation above the clinically discriminant cut-off values were significantly predictive of outcome at long-term follow up. CONCLUSIONS cTnI proved to be the most sensitive marker in detecting myocardial necrosis following PCI. CK-MB, cTnT and cTnI all provided similarly reliable prognostic information, with cTnT and cTnI being marginally superior in predicting MACE at follow up.

Prognostic role of cardiac troponin I after percutaneous coronary intervention in stable coronary disease

Objective: To assess the role of cardiac troponin I (cTnI) in predicting outcome after percutaneous coronary intervention (PCI). Methods and results: cTnI was measured immediately before and at 6, 14, and 24 hours after PCI in 316 consecutive patients with stable symptoms and native coronary artery disease. The study end point was the occurrence of major adverse cardiac events (MACE) at 30 days and at 18 months after PCI: death, Q wave myocardial infarction (MI), or repeat revascularisation in hospital. Postprocedural cTnI increased in 31% of patients. The cumulative MACE rate at 18 months was 25% (17.7% due to repeat PCI procedures). There was a significant association between postprocedural cTnI increase and death, Q wave MI, or both (odds ratio (OR) 3.28, 95% confidence interval (CI) 1.7 to 6.4, p  =  0.01). Post-PCI cTnI increase had a positive predictive value (PPV) for adverse events at 18 months of 0.47 and a negative predictive value (NPV) of 0.96 (OR 18.9, 95% CI 9.7 to 37, p < 0.0001). The presence of both a postprocedural cTnI rise and a procedural angiographic complication gave a PPV for adverse events of 0.69 and an NPV of 0.92 (OR 22.6, 95% CI 2.6 to 68.6, p  =  0.0005). Conclusions: cTnI increased post-procedurally in one third of this stable patient population undergoing elective PCI and was independently and significantly predictive of an increased risk of adverse events at 18 months, predominantly in the form of repeat PCI.

Randomised trial of elective stenting after successful percutaneous transluminal coronary angioplasty of occluded coronary arteries

Background The value of angioplasty in occluded coronary arteries is limited by a restenosis/reocclusion rate of 50–70%. In patients with subtotal occlusion, stent implantation has been shown to reduce clinical and angiographic restenosis. Retrospective observational studies have suggested that stenting could reduce restenosis in total occlusions. The value of sustained coronary patency on global and regional left ventricular function in this clinical setting has not been defined clearly. Objectives To assess the medium term effect of elective intracoronary stent deployment after successful percutaneous transluminal coronary angioplasty (PTCA) of an occluded coronary artery. Methods Sixty patients with a total coronary occlusion successfully treated by PTCA were randomised to receive an intracoronary stent or no stent. Patients underwent clinical and angiographic follow up at six months. Results Thirty patients received a stent (group A) and 30 were treated by angioplasty alone (group B), all with initial success. One patient in group B required repeat angioplasty with stenting at 24 hours and one patient died after 10 days. Angiographic follow up was available for 57 patients. This showed a significantly reduced reocclusion rate in group A compared with group B (7% v 29%, p < 0.01) and a tendency to a reduced restenosis rate (22% v 40%, p = 0.105) in patients with no reocclusion. Left ventricular function, both global and regional, improved in group A. Only the regional left ventricular function in the area supplied by the target coronary artery improved in group B. Recurrence of symptoms and clinical events such as repeat angioplasty, coronary artery bypass grafting, death or myocardial infarction tended to be reduced in group A (4 (13%) v 9 (30%)). Conclusions Intracoronary stent insertion is effective in reducing the rate of reocclusion and shows a trend towards reduced restenosis after opening of a total coronary occlusion by balloon angioplasty. Sustained patency of the target coronary artery is associated with improvement in global and regional left ventricular function.

Transesophageal Echocardiography in the Detection and Surgical Management of a Papillary Fibroelastoma of the Mitral Valve Causing Partial Mitral Valve Obstruction

Primary mitral valve tumors are rare. We describe the transesophageal appearances of a papillary fibroelastoma (Lambls giant excrescence) of the anterior mitral valve leaflet causing partial mitral valve obstruction. Transesophageal echocardiography proved particularly useful in identifying the limited attachment of the tumor to the anterior mitral valve leaflet and excluding its attachment to the interatrial septum. These features helped to exclude the possibility of the tumor being a left atrial myxoma, the primary differential diagnosis of the lesion. Transesophageal echocardiography enabled the planned surgical option to be mitral valve repair and also allowed intraoperative monitoring to assess the results of the surgical repair.

High-Speed Rotational Atherectomy in the Treatment of Bifurcation-Type Coronary Lesions

Background: Bifurcational coronary lesions present a major interventional challenge. The differential cutting mechanism of high-speed rotational atherectomy (HSRA) may provide a favourable technique of treating this complex lesion subtype. Methods: We evaluated the use of HSRA (32 lesions) compared to balloon angioplasty (BA) (118 lesions), with provisional stenting in both groups, in a non-randomised, retrospective study of 150 bifurcation-type lesions. Results: The HSRA/stent group had a high primary success rate of 97%, an acceptably low in-hospital event rate of 9% and an overall major adverse cardiac event (MACE) rate at a mean follow-up period of 15 ± 3.4 months of 22.5% with a target lesion revascularisation (TLR) rate of 18.7%. Procedural success in the BA/stent group was 81% with an in-hospital event rate of 14.4%, and the overall MACE rate at follow-up was 27.5% with a TLR rate of 23%. We achieved a greater acute gain in minimal luminal diameter and a lesser percentage of residual stenosis after intervention in the HSRA/stent group compared to the BA/stent group (p < 0.01). Outcome at follow-up favoured the HSRA/stent group, although the difference did not reach statistical significance. Conclusion: HSRA with provisional stenting provided a safe and effective means of treating bifurcation lesions.

Echocardiographic restenosis after successful balloon dilatation of the mitral valve with the Inoue balloon: experience of a United Kingdom centre.

OBJECTIVES--(a) To assess the echocardiographic incidence of restenosis after successful balloon dilatation of the mitral valve at a mid-term follow up of one year among a population of predominantly United Kingdom patients. (b) To identify any factors, assessed before or during dilatation, which may predict the development of restenosis. DESIGN--Successful dilatation of the mitral valve was defined as an increase in mitral valve area of > 25% and a final valve area of at least 1.5 cm2. Echocardiographic restenosis was defined at follow up as a loss of 50% of initial gain and a valve area of less than 1.5 cm2. Mitral valve area was assessed by transthoracic echocardiography before, during, 48 hours after, and one year after successful balloon dilatation of the mitral valve. Echo score before dilatation (an assessment of valvar and subvalvar calcification, thickening, and mobility), age, rhythm, echocardiographic mitral valve area before and after dilatation, left atrial pressure before and after dilatation, and end diastolic mitral valve gradient before and after dilatation were compared in those patients with and without echocardiographic restenosis at one year. SETTING--A regional cardiothoracic centre in the United Kingdom that performs 20-30 balloon dilatations of mitral valves each year. PATIENTS--39 patients, with symptomatic dominant mitral stenosis, who had undergone successful balloon dilatation of the mitral valve, and in whom echocardiographic assessment of mitral valve area was available at one year. 92% of patients were citizens of the United Kingdom. INTERVENTIONS--Balloon dilatation of the mitral valve by the Inoue technique. MAIN OUTCOME MEASURES--Mitral valve area and patient symptom class (New York Heart Association) one year after successful dilatation of the mitral valve. RESULTS--The incidence of echocardiographic restenosis was eight of 39 patients (21%). Of the eight patients with restenosis four underwent mitral valve replacement, two had repeat dilatation of the mitral valve, and two remained on medical treatment. With univariant analysis, factors associated with restenosis were increased age, higher echo score before dilatation, and a lower mitral valve area immediately after the operation. The only independent risk factor for restenosis, shown by multivariant analysis, was a high echo score before dilatation. There was no significant fall in mitral valve area at one year in those patients without restenosis. Most (28/31) of these patients had echocardiographic evidence of splitting of at least one commissure after dilatation compared with only two of eight patients who developed restenosis. Of 10 patients with an echo score before dilatation > or = 10 only two had an initially successful operation and no restenosis at one year. CONCLUSIONS--The echocardiographic incidence of restenosis after dilatation of the mitral valve by the Inoue technique in patients of the United Kingdom is 21%. The principal factor associated with restenosis is a high echo score before dilatation. Increases in mitral valve area are maintained in those patients without restenosis and it is likely that the mechanism of initial increase in valve area is different in the two groups, being commissural splitting in those patients who do not get restenosis and valve stretching in those that do. In patients with an echo score > or = 10 dilatation of the mitral valve should be considered only as a palliative procedure.

Coronary-Artery Rupture Treated with a Polytetrafluoroethylene-Coated Stent

To the Editor: Coronary-artery rupture is a rare but well-recognized complication during percutaneous revascularization1 that usually requires urgent surgical intervention and often has a poor or f...

Cardiac troponin I for risk stratification following percutaneous coronary artery intervention in acute coronary syndromes

The cardiac troponins have been shown to provide prognostic information allowing risk stratification of patients with acute coronary syndromes (ACS). The benefit of early percutaneous coronary intervention (PCI) in this setting has been highlighted by the FRISC II study. We assessed the pattern of release of cardiac troponin I (cTnI) following PCI in patients with ACS and evaluated its prognostic value for major adverse cardiac events (MACE): death, Q‐wave myocardial infarction (QWMI), and repeat revascularization at follow‐up. cTnI was sampled at baseline and 6, 14, and 24 hr following PCI in 73 patients presenting with unstable and post‐MI angina. Clinical follow‐up was obtained in all 73 patients at a mean period of 43 ± 19.9 weeks (range, 11–68 weeks). Patients were stratified into two groups according to whether cTnI remained unchanged or fell below baseline 24 hr post‐PCI (group 1, n = 47) or increased above baseline 24 hr following PCI (group 2, n = 26). MACE occurred in 4 (8.5%) of patients in group 1 (QWMI = 1, CABG = 1, re‐PCI = 2) and in 19 (73%) of patients in group 2 (death = 1, QWMI = 2, CABG = 2, re‐PCI = 14; chi‐square = 32.34, P < 0.0001). The positive predictive value of rising cTnI within 24 hr following PCI for MACE at follow‐up was 0.73 and the negative predictive value was 0.92 (specificity = 83%, sensitivity = 86%; odds ratio = 29.18, 95% CI = 7.62–110.64, P < 0.0001). cTnI is an inexpensive and widely applicable tool that offers reliable prognostic information for the risk stratification of patients undergoing coronary revascularization in the setting of acute coronary syndromes and may identify a group of patients at particular risk of repeat PCI. Cathet Cardiovasc Intervent 2002;55:37–42.