P5620Clinical and hemodynamic determinants of coronary flow reserve in non-obstructed coronary arteries - A patient level pooled analysis of the DEBATE and ILIAS studies

Aim

Coronary Flow Reserve (CFR) is a valuable physiological index for the assessment of myocardial flow impairment due to focal or microcirculatory coronary artery disease (CAD). Coronary flow capacity (CFC) is another flow-based concept in diagnosing ischemic heart disease (IHD), based on hyperemic average peak velocity (hAPV) and CFR. We evaluated clinical and hemodynamic factors which potentially influence CFR and CFC in non-obstructed coronary arteries.

Methods

We analysed CFR and CFC of 396 non-obstructed vessels of patients from two large multi-center trials (DEBATE and ILIAS) with stable CAD who were scheduled for percutaneous coronary intervention (PCI). Doppler flow measurements were performed after inducing hyperemia with either intracoronary or intravenous infusion of adenosine.

Results

Akaike's Information Criterion (AIC) revealed the parameters age, female gender, a history of myocardial infarction, hypercholesterolemia, current or previous smoking and rate pressure product (RPP) as independent predictors in the best model of fit for CFR in an angiographically non-obstructed vessel. After multivariate regression analysis age, female gender and RPP remained as determinants of CFR in angiographically non-obstructed vessels. Subsequently, ordered logistic regression analysis revealed that age is associated with a worse CFC.

Conclusion

Clinical and hemodynamic parameters are associated with CFR and to a lesser extent CFC in an angiographically non-obstructed coronary artery. CFC is less sensitive to variations in clinical and hemodynamic parameters than CFR and therefore a promising tool in contemporary clinical decision making in the cardiac catheterization laboratory.

Acknowledgement/Funding

DEBATE: Cardiometrics INC. ILIAS: Dutch Health Insurance Board; RADI Medical Systems, Uppsala, Sweden; and Endosonics, Rancho Cordova, CA.

122Mechanism and impact of lesion morphology on the late lumen loss of drug-eluting resorbable magnesium scaffolds: a serial optical coherence tomography study

Introduction

Resorbable Magnesium Scaffolds have demonstrated favourable clinical results with acceptable late lumen loss (LLL). However, the pathomechanisms influencing LLL of resorbable sirolimus-eluting metallic scaffold (Magmaris) have not been analyzed.

Purpose

Using serial optical coherence tomography (OCT), we investigated potential factors, i.e. the contribution of recoil versus neointimal hyperplasia (NIH).

Methods

Patients who were enrolled into BIOSOLVE-II, and underwent serial angiography and OCT (baseline and follow-up: 6-month and/or 1-year) were analyzed. Patients were divided into 2 groups based on angiographic in-scaffold LLL <0.5mm or ≥0.5mm. Endpoints were late absolute recoil and NIH area as assessed by OCT.

Results

A total of 70 patients (LLL <0.5mm: n=41, LLL ≥0.5mm: n=29) were serially analyzed. Patient and lesion characteristics were comparable and there was no significant difference in mean and minimal scaffold area between groups at baseline. Late absolute recoil was significantly smaller among patients with LLL <0.5mm (0.53±0.68 mm2) compared with those with LLL ≥0.5mm (1.48±1.20 mm2, P<0.001) (Figure). A small difference in NIH area at follow-up was observed (LLL <0.5mm: 1.47±0.33 mm2 vs. LLL ≥0.5mm: 1.68±0.34 mm2, P=0.013). In a matched-frame analysis (baseline and follow-up), late absolute recoil varied according to the underlying plaque type (lipid: 0.63±1.23 mm2, calcified: 0.81±1.44 mm2, and fibrous: 1.20±1.52 mm2, P<0.001), while there was no difference with regards to NIH area (P=0.132).

Conclusion

The main driver of late lumen loss of sirolimus-eluting absorbable metal scaffold was late scaffold recoil, while the contribution of NIH was modest. The degree of late scaffold recoil depended on the underlying plaque type and was highest among fibrotic lesions. Future studies will address the impact of procedural factors such as adequate lesion preparation and post-dilatation.

Acknowledgement/Funding

Biotronik

[Acute coronary syndrome with ST-elevation]

The current guidelines of the European Society of Cardiology have up-dated and confirmed the role of a primary percutaneous coronary intervention (PCI) as the preferred reperfusion therapy in patients with acute coronary syndrome and ST-elevation. The establishment of regional network structures for implementation of this reperfusion strategy is recommended and described. Primary PCI should preferably be carried out via the transradial route and should include the implantation of modern drug-eluting stents. In most cases of coronary multivessel disease, primary PCI should be limited to the treatment of the infarcted artery. Routine mechanical thrombus aspiration during primary PCI is no longer recommended. Recommendations for a specific anti-thrombotic and secondary prophylactic medication after primary PCI are highlighted.

The German CPU registry: Comparison of smokers and nonsmokers

BACKGROUND

Chest pain is a major reason for admission to an internal emergency department, and smoking is a well-known risk factor for coronary artery disease (CAD) and acute coronary syndrome (ACS). The aim of this analysis is to illustrate the differences between smokers and nonsmokers presenting to German chest pain units (CPU) in regard to patient characteristics, CAD manifestation, treatment strategy, and prognosis.

METHODS

From December 2008 to March 2014, 13,902 patients who had a complete 3‑month follow-up were enrolled in the German CPU registry. The analysis comprised 5796 patients with ACS and documented smoking status.

RESULTS

Of all the patients in the CPU registry, 35.2% were smokers. Compared with nonsmokers, they were 13.5 years younger (58.2 vs. 71.7 years, p < 0.001), predominantly men (77.1% vs. 65.2%, p < 0.001), and were more frequently diagnosed with single-vessel disease (32.1% vs. 25.2%) as well as ST-elevation myocardial infarction (STEMI; 23.8% vs. 15.5%, p < 0.001). Although the Global Registry of Acute Coronary Events (GRACE) Risk Score for hospital mortality was lower in the group of smokers (106.1 vs. 123.3, p < 0.001), we did not observe any differences in CPU death (0.4% vs. 0.4%, p = 0.69) and CPU major adverse cardiac event (MACE) rates (3.8% vs 2.9%, p = 0.073) between the groups. In the 3‑month follow-up, we documented higher mortality rates in the nonsmoker group (1.9% vs. 2.9%, p = 0.035) in correlation with the GRACE Risk Score (80.3 vs. 105.2, p < 0.001). MACE rates were similar during the follow-up (3.1% vs. 4.1%, p = 0.065).

CONCLUSION

Observations from the German CPU registry demonstrate that smoking is a strong predictor of acute CAD manifestation early in life, especially STEMI. In spite of a lower GRACE Risk Score and fewer comorbidities, smokers had a rate of hospital mortality similar to the older group of nonsmokers.

Assessment of coronary morphology and flow in a patient with Guillain-Barré syndrome and ST-segment elevation

Patients with Guillain-Barré syndrome often have cardiac disturbances as a manifestation of autonomic dysfunction. Such abnormalities consist of arrhythmias and disturbances of heart rate and blood pressure. We report a case of a patient with Guillain-Barré syndrome who developed ST-segment elevation in the inferolateral leads, suggestive of an acute coronary syndrome. Cardiac catheterization revealed angiographically normal coronary arteries. Intracoronary ultrasound was also normal. Intracoronary Doppler flow measurements revealed an elevated baseline coronary flow velocity of up to 41 cm/s and decreased coronary flow reserve, particularly in the left circumflex artery. Myopericarditis as cause of the electrocardiographic changes could be ruled out by echocardiography and endomyocardial biopsy. We postulate that the intracoronary Doppler findings are caused by autonomic dysfunction with decrease of coronary resistance and redistribution of the transmural myocardial blood flow.

Distal embolic protection during percutaneous intervention of aorto-coronary venous bypass grafts: The FIRST Trial

OBJECTIVE

Interventions in aorto-coronary venous bypass grafts (CABG) can cause acute procedural complications due to distal embolization of debris. In the FIRST (First European Investigation Regarding the Systematic use of the TriActiv device) multicenter trial the distal endovascular protection system TriActiv (Kensey Nash) was evaluated during intervention of CABG.

METHODS

195 patients in 17 centers in Germany with significant disease of a vein graft were enrolled. Inclusion and exclusion criteria were comparable to the SAFER trial.

RESULTS

Acute procedural success was achieved in 98% of cases. Aspirated debris was found in 96.5% of patients. Primary endpoints (MACE at 30 days) occurred in 8.7% of all pts. (ITT). No patient died and 7.2% of patients suffered from MI. The rate of early revascularization was 1.5%. Secondary endpoints (MACCE at 30 days) were found in 9.2% and at hospital discharge in 8.7% of patients.

CONCLUSIONS

The TriActiv system is safe and effective. Normal post procedural flow can be preserved and the MACE rate is with 8.7% considerably low. The FIRST trial supports the growing belief that PCI of CABG should be performed with protection systems.

Postinterventional homocysteine levels: Failure as a predictive biomarker of in-stent restenosis

OBJECTIVES

Purpose of our study was to determine if homocysteine plasma levels are related to the risk of in-stent restenosis after percutaneous coronary stent implantation in de novo lesions.

BACKGROUND

The putative role of homocysteine as a predictive cardiovascular biomarker of coronary artery disease is well established. The impact of homocysteine levels in the development of in-stent restenosis, however, is controversially discussed.

METHODS

A total of 177 patients with stable angina pectoris undergoing stent implantation in coronary de novo lesions were included. Laboratory determination comprised blood sample evaluation for homocysteine and other conventional risk factors before baseline coronary intervention and prior to six months control catheterization. Binary restenosis, late lumen loss, and late loss index after six months were assessed by quantitative coronary angiography. Endpoints included target lesion and target vessel failure, homocysteine levels as well as major adverse cardiac events.

RESULTS

There was a significant correlation between the length of the implanted stent (p<0.006), the percentage of stenosis (p<0.003) and the pre-interventional luminal diameter (p<0.0001) with late loss index. Linear regression analysis demonstrated no significant impact of the initial or six months homocysteine levels on angiographic restenosis, late lumen loss, or late loss index.

CONCLUSIONS

In contrast to homocysteine levels, luminal diameter, stent length and percentage of stenosis correlated with the appearance of restenosis. Taking our data into consideration, we hypothesise that homocysteine may not serve as a safe and independent biomarker of in-stent restenosis after a six months period following percutaneous coronary stenting.

Insulin sensitivity and coronary vasoreactivity: insulin sensitivity relates to adenosine-stimulated coronary flow response in human subjects

OBJECTIVE

Diabetes is associated with coronary microvasculature abnormalities and impaired coronary flow reserve (CFR). CFR is the ratio of coronary flow under maximal vasodilation to basal flow and is a measure for coronary vasoreactivity. Insulin resistance is the central defect in the development of type 2 diabetes, preceding its onset by 10-20 years. Thus, the relationship between insulin sensitivity and CFR in nondiabetic subjects is particularly interesting. The aim of the study was to investigate this relationship.

DESIGN

Cross-sectional study.

PATIENTS

The study population consisted of 18 nondiabetic subjects without coronary artery stenosis on coronary angiography. We excluded patients with structural heart disease or with conditions affecting CFR or insulin sensitivity such as low density lipoprotein (LDL)-cholesterol > or = 4.14 mmol/l, smoking, hypertension or obesity with a body mass index (BMI) > 28 kg/m(2).

MEASUREMENTS AND RESULTS

CFR was 3.1 +/- 0.8 (range 1.7-4.8), as assessed by intracoronary Doppler measurements in the left anterior descending coronary arteries after adenosine stimulation. Intravascular ultrasound revealed zero to moderate coronary atherosclerotic changes. Whole-body insulin sensitivity (M-value) was 7.5 +/- 2.9 mg/kg/min (range 2.2-12.6), as assessed by the hyperinsulinaemic-euglycaemic clamp test. Subjects with low CFR (< 3.0) had a significantly lower M-value than subjects with normal CFR (> 3.0) (6.0 +/- 2.5 vs. 9.0 +/- 2.5 mg/kg/min, P = 0.021). Univariate linear regression demonstrated a strong correlation between CFR and M-value (r = 0.76, P < 0.001). In multiple regression analysis, the significant association of CFR with M-value was independent of potential confounders (sex, age, BMI, LDL-cholesterol and plaque burden on intravascular ultrasound). Bootstrap analysis corroborated this finding.

CONCLUSIONS

Whole-body insulin sensitivity relates to coronary vasoreactivity. Across a wide range of both insulin sensitivity and coronary flow reserve from markedly abnormal to normal values, an increase in insulin sensitivity appears to be associated with an increase in coronary flow reserve. Insulin resistance is therefore associated with coronary microvasculature abnormalities in nondiabetics.

Acute and long-term outcome after coronary artery perforation during percutaneous coronary interventions

BACKGROUND

Coronary artery perforation is a rare but serious complication of percutaneous coronary interventions (PCI).

METHODS

We reviewed our database for cases of overt coronary perforation during PCI procedures. Hospital charts, procedural reports, and coronary angiograms of these patients were reviewed, with particular emphasis on mechanisms of perforation, management of the complication, and clinical outcome.

RESULTS

Between 01/1998 and 12/2003, a total of 19 cases (mean age: 66+/-8 years, 13 male) of coronary perforation occurred during 6433 PCI procedures performed within this period (incidence: 0.3%). In 12/19 (63%) cases, perforation occurred during recanalisation procedures of chronic total occlusions of coronary arteries. In all but one patient, non-surgical management was attempted: 2 out of 19 (11%) patients were treated conservatively by reversal of heparin anticoagulation. Prolonged balloon inflation at the perforation site was applied in 10/19 (53%) patients. Six (32%) patients received stents (5 of them received covered stentgrafts), 3 (16%) patients developed cardiac tamponade requiring percardiocentesis, and only 2 (11%) patients underwent bailout surgical repair. There were 2 (11%) deaths early after the procedure.

CONCLUSION

Coronary perforation during PCI is a rare complication, but is associated with significant morbidity and mortality. In the majority of patients, non-surgical management is both feasible and associated with a high success-rate.

[Minimally invasive quantitation of myocardial microvascular function using computed tomography: the blood volume-to-flow relationship]

The intramyocardial coronary microvasculature has an important role in regulating regional myocardial perfusion. Pathologic alterations of microvascular function may be present in early stages of coronary artery disease, myocardial hypertrophy, cardiomyopathy or systemic diseases such as arterial hypertension and diabetes mellitus. Fast computed tomography permits noninvasive simultaneous quantitation of regional intramyocardial blood volume and myocardial perfusion using indicator dilution principles. Our data indicate that especially the blood volume-to-flow relationship is sensitive enough to characterize and quantitate the functional impact of different pathologies along the coronary tree on microvascular function. This could be demonstrated for 1) acute impairment of microvascular function following coronary microembolization, 2) endothelial dysfunction induced by chronic hypercholesterolemia, 3) chronic epicardial non-significant stenoses, 4) physiologic maturation of the normal microvasculature and 5) quantification of heterogeneity of microvascular function. These findings, the methodological background and the concept itself are presented in this article. Application of the blood volume-to-flow relationship is not limited to fast-CT but may be used in any cross sectional imaging technique, such as MRI or echocardiography, as long as intramyocardial blood volume and perfusion can be quantitated simultaneously. This new noninvasive approach to the quantification of intramyocardial microvascular function may prove a useful adjunct to those imaging techniques that are used to noninvasively quantitate epicardial stenoses or regional wall motion abnormalities.

Genetic variation of the platelet- surface integrin GPIIb-IIIa (PIA1/A2-SNP) shows a high association with Type 2 diabetes mellitus

AIMS/HYPOTHESIS

The gene encoding the beta(3)-subunit (GPIIIa) of the platelet alpha(2)beta(3)-integrin (fibrinogen receptor) shows a polymorphism PlA1/A2 with the A2 allele putatively associated with an increased risk of acute ischaemic events. This study investigated whether Type 2 diabetes as a particular macrovascular risk factor associates with the thrombogenic PIA2 genotype.

METHODS

The PlA genotype was determined in 112 consecutive Type 2 diabetic patients additionally classified according to the presence of macrovascular disease. Forty-four non-diabetic patients with angiografically documented cardiovascular disease (CAD/ AMI) and a further 59 non-diabetic subjects with no angiografical signs of CAD were investigated as genomic background control (n=103). PIA-genotyping was carried out by standard restriction fragment length analysis (RFLA) of PCR amplified lymphocyte template DNA.

RESULTS

The overall allelic PlA2- prevalence accounted to 34.8% (39/112) in diabetic patients as compared to 14.6% (15/103) in non-diabetic patients [OR 3.1 (1.6-6.1), p<0.01]. This odds ratio increased to 7.0 (2.5-19.7), (p<0.01) in subjects free of criteria of macrovascular disease. In non-diabetic control subjects without CAD there was an allelic PIA2 frequency of 10.2% (6/59) as compared to 20.5% (9/44) in patients with CAD and a history of AMI being less than either diabetes subgroup. The PIA2 prevalence in the subgroup of diabetes patients with macrovascular complications did not differ from the respective value in patients without macrovascular disease. [29.0% (20/69) vs. 44.2% (19/43)].

CONCLUSION/INTERPRETATION

This study confirms a trendwise association of PlA2 with severe coronary artery disease, but rather suggests an even stronger, highly significant association with the metabolic condition of Type 2 diabetes mellitus. This justifies the speculation that pathways dependent on the platelet alpha(2)beta(3) integrin physiology could be implicated in the pathogenesis of Type 2 diabetes which lends further support to the "common soil" hypothesis of diabetes and vascular disease.

[Brachytherapy after coronary interventions: current state and future perspectives]

Intracoronary brachytherapy is a novel, meanwhile established therapy. It is currently the only interventional procedure which has proven to effectively reduce the restenosis rates after intervention of long and diffuse in-stent restenosis. For this indication, brachytherapy can be regarded as the current treatment of choice. Randomized studies yield promising results for bypass interventions or interventions in small vessels or diabetic patients. These findings may encourage the decision to perform a percutaneous, transluminal intervention in such high-risk patients. In clinical practice, implantation of new stents in combination with brachytherapy procedures should be avoided as far as possible. In any case, the combined antiaggregatory therapy should be conducted sufficiently long to minimize the danger of late stent thrombosis. Under this treatment, the expected thrombosis rates ar within the range of placebo-treated patients. The length of the radiation source should be sufficient to cover the entire interventional injury length to avoid recurrent edge stenosis. De novo lesions are currently not a routine indication for intracoronary brachytherapy. Although intracoronary brachytherapy may effectively reduce restenosis rates in sufficiently irradiated de novo lesion segments, de novo lesions should be treated only within the set-up of controlled studies. The current available data with a follow-up period of up to 5 years show that intracoronary brachytherapy is also in the mid-term a safe and effective therapy for the reduction of restenosis after coronary interventions.

Evaluation of metal allergies in patients with coronary stents

In-stent restenosis is a complication which impairs the success of coronary stenting. Recently, it was supposed that a delayed hypersensitivity reaction to nickel and molybdenum might be one of the triggering factors in in-stent restenosis. We have analyzed the data collected in our centre with respect to this hypothesis. Altogether, 34 patients were investigated (24 male, 10 female). Patch tests were performed with the standard series of the German Contact Dermatitis Research Group and a metal series containing the metal components of 316 L stainless steel. A positive patch test reaction to nickel was observed in 4 (11.8%) patients. None of the patients showed sensitization to the other metals. Retrospective analysis was performed in 20 patients: 2 of these patients had a positive patch test reaction to nickel, one of whom had an in-stent restenosis, and the other not. Restenoses were predominantly observed in patients with negative patch test reactions to nickel (6/18 patients). Out of the patients who were investigated prospectively only one showed sensitization to nickel. Restenosis was observed in 2 patients: neither patient had nickel allergy. Although it still cannot be excluded that metal allergy may play a role in the restenosis process in coronary stenting, there is at present little evidence for it.

Prognostic implication of cardiac troponin T increase following stent implantation

OBJECTIVE

To identify the incidence and clinical significance of myocardial injury following elective stent implantation.

DESIGN

Prospective clinical study with 278 consecutive patients undergoing stenting of de novo coronary or saphenous vein graft lesions. Incidence of periprocedural myocardial injury was assessed by analysis of 12 lead ECG, creatine kinase (CK; upper limit of normal (ULN) 70 IU/l for women, 80 IU/l for men), and cardiac troponin T (cTnT; point of care test; threshold 0.1 ng/ml) before and 6, 12, and 24 hours after the intervention. Major adverse cardiac events (MACE: acute myocardial infarction, bypass surgery, and cardiac death) were recorded during clinical follow up (mean (SD) 7.8 (5.3) months).

RESULTS

Following elective stenting, the rate of a positive cTnT status was 17.3%, the rate of CK increase of 1-3x ULN 14.7%, the rate of CK increase of > 3x ULN 1.4%, and the rate of Q wave myocardial infarction 0.4%. Cardiac mortality during follow up was higher in patients with postprocedurally increased CK (7.1% v 1.3%, p = 0.01, log rank) and cTnT (9.1% v 0.9%, p < 0.001, log rank). In addition, postprocedurally increased cTnT was associated with a higher overall incidence of MACE (13.1% v 4.0%, p < 0.01, log rank) and was identified as an independent factor for MACE during follow up (hazard ratio 3.27, 95% confidence interval 1.14 to 9.41, p = 0.028).

CONCLUSIONS

Following elective stent implantation, a positive cTnT status identified patients at risk of a worse long term outcome. Treatment strategies have to be developed that lead to prognostic improvement by reducing periprocedural myocardial injury.

Coronary microembolization

Atherosclerotic plaque rupture is a key event in the pathogenesis of acute coronary syndromes and during coronary interventions. Atherosclerotic plaque rupture does not always result in complete thrombotic occlusion of the entire epicardial coronary artery with subsequent acute myocardial infarction; however, in milder forms it may result in the embolization of atherosclerotic and thrombotic debris into the coronary microcirculation. The present report summarizes the available morphologic evidence for coronary microembolization in patients who died of coronary artery disease, especially sudden death. The report then goes on to address the experimental pathophysiology of coronary microembolization in animal models of acute coronary syndromes and heart failure. Finally, the report presents the available clinical evidence for coronary microembolization, highlights its key features--arrhythmias, contractile dysfunction, infarctlets and reduced coronary reserve--and addresses prevention by mechanical protection devices and glycoprotein IIb/IIIa antagonism.

Increased heterogeneity of coronary perfusion in patients with early coronary atherosclerosis

BACKGROUND

In patients with typical angina but angiographically normal coronary arteries, abnormal vasomotor function is assumed to be a major underlying cause. However, data on this issue are conflicting, and recent studies suggest that fluid dynamic abnormalities exist in these patients. The aim of the study was to evaluate whether early stages of atherosclerosis are characterized by alterations of baseline coronary hemodynamics and endothelium-independent vasomotion. Besides established intracoronary Doppler parameters, heterogeneity of perfusion was assessed and related to early signs of atherosclerosis as determined by electron-beam computed tomography (EBCT).

METHODS

In 59 patients with typical angina and angiographically normal or near-normal coronary arteries, intracoronary Doppler measurements were performed in all 3 major coronary arteries. Baseline average peak velocity (bAPV) and hyperemic average peak velocity (hAPV) in response to intracoronary injection of adenosine were measured, and coronary flow velocity reserve (CFVR) was calculated. Heterogeneity was assessed as variability of bAPV, hAPV, and CFVR and was calculated as (STD/MEAN). 100. Doppler data were analyzed according to tertiles of the EBCT-derived Agatston calcium score (ie, score 0-1 [lowest tertile], 2-28 [medium tertile], and >28 [highest tertile]).

RESULTS

The mean EBCT-derived Agatston calcium score was 49 +/- 107. No coronary calcium was observed in 17 (29%) patients. The mean values of bAPV, hAPV, and CFVR were not different between the calcium score tertiles. However, patients in the highest tertile had a significantly increased variability index of bAPV (29.6% +/- 11.6%) compared with patients in the lowest tertile (13.4% +/- 7.3%, P <.0001). Variability of CFVR was also increased in these patients (15.5% +/- 11.7% vs 10.5% +/- 4.0%, P =.03).

CONCLUSION

These results indicate that early stages of atherosclerosis are characterized by microvascular abnormalities that do not uniformly affect the myocardium but are heterogeneous. The high variability of baseline coronary flow velocity with increasing coronary calcium suggests that in patients with early stages of atherosclerosis fluid dynamic effects may play a crucial role even in the absence of angiographically appreciable epicardial stenoses.

The immediate and long-term effect of optimal balloon angioplasty on the absolute coronary blood flow velocity reserve. A subanalysis of the DEBATE study. Doppler Endpoints Balloon Angioplasty Trial Europe

BACKGROUND

There are limited data regarding the immediate and long-term effect of balloon angioplasty on the coronary flow reserve evaluated in a multicentre setting.

METHODS AND RESULTS

A total of 86 patients with one-vessel disease and normal left ventricular function were analysed before and after optimal balloon angioplasty (diameter stenosis <35%) and at 6-month follow-up. Coronary flow reserve was assessed with a Doppler guide wire. A low coronary flow reserve (<or=2.5) after PTCA, due to an increased baseline blood flow velocity, was encountered in 42 of the 86 patients (49%). Recurrence of angina and target lesion revascularization were more frequent in these patients than in patients with a coronary flow reserve >2.5 (46% vs 23% and 36% vs 16%, respectively; P<0.05) due to a trend towards restenosis (29% vs 16%; P=0.15) or a low coronary flow reserve at follow-up due to persistent elevated baseline blood flow velocity. Patients without restenosis showed a decrease or increase of coronary flow reserve during follow-up, determined by alterations of hyperaemic blood flow velocity.

CONCLUSIONS

Patients with an impaired coronary flow reserve directly after optimal balloon angioplasty showed a higher target lesion revascularization rate compared to patients with a coronary flow reserve >2.5. This patient group consists of patients prone to develop restenosis, while other patients are characterized by a persistently low coronary flow reserve, probably secondary to disturbed autoregulation and/or diffuse mild coronary atherosclerosis. Coronary flow reserve alterations in patients without restenosis were related to changes in hyperaemic blood flow velocity, suggesting that this phenomenon relates to epicardial remodelling.

Early clinical experience with the 6 French Angio-Seal device: immediate closure of femoral puncture sites after diagnostic and interventional coronary procedures

The objective of this study was to assess the early safety and efficacy of the novel 6 Fr Angio-Seal device for routine clinical use after diagnostic cardiac catheterization and coronary angioplasty. In a prospective study, we used the 6 Fr Angio-Seal device in 180 consecutive patients (131 male, 49 female, mean age 60.7 years) for closure of femoral arterial puncture sites immediately after diagnostic (n = 108) or interventional (n = 72) coronary procedures independent of the coagulation status. All patients were monitored for 24 hr after the procedure and followed for 30 days. The closure device was successfully deployed in 95.4% after diagnostic catheterization versus 98.6% after coronary angioplasty (P = 0.963). Immediate hemostasis was achieved in 91.5% versus 90.1% of the patients (P = 0.993). Major complications were observed 1.9% versus 2.8% of the patients (P = 0.885). During 30-day follow-up, no late events or complications were reported. The 6 Fr Angio-Seal device is a safe and effective device that allows for immediate closure of femoral puncture sites after both diagnostic and interventional procedures with a low rate of major complications.

Plaque distribution and vascular remodeling of ruptured and nonruptured coronary plaques in the same vessel: an intravascular ultrasound study in vivo

OBJECTIVES

This study was designed to identify potential differences between the intravascular ultrasound (IVUS) characteristics of spontaneously ruptured and nonruptured coronary plaques.

BACKGROUND

The identification of vulnerable plaques in vivo may allow targeted prevention of acute coronary events and more effective evaluation of novel therapeutic approaches.

METHODS

Intravascular ultrasound was used to identify 29 ruptured plaques in arteries containing another nonruptured plaque in an adjacent segment. Intravascular ultrasound characteristics of these plaques were compared with plaques of computer-matched controls without evidence of plaque rupture. Plaque distribution was assessed by measuring the eccentricity of lumen location (inside the total vessel). Lumen cross-sectional area narrowing was calculated as [1 - (target/reference lumen area)] x 100%. A remodeling index was calculated as lesion/reference arterial area (>1.05 = compensatory enlargement, <0.95 = shrinkage).

RESULTS

Among the three groups of plaques, there was no significant difference in quantitative angiographic parameters, IVUS reference dimensions and IVUS lumen cross-sectional area narrowing. There was a difference in plaque distribution; lumen location by IVUS was significantly more eccentric in ruptured than in nonruptured (p = 0.002) and control plaques (p < 0.0001). The arc of disease-free vessel wall was larger in ruptured than in control plaques (p < 0.0001). The remodeling pattern of ruptured and nonruptured plaques differed significantly from that of the control plaques (p = 0.0001 and 0.003); compensatory enlargement was found in 66%, 48%, and 17%, whereas shrinkage was found in 7%, 10% and 48%, respectively.

CONCLUSIONS

Intravascular ultrasound assessment of plaque distribution and vascular remodeling may help to classify plaques with the highest probability of spontaneous rupture.

Abnormal Coronary Flow Velocity Reserve After Coronary Intervention Is Associated With Cardiac Marker Elevation

Background —Residual reduction of relative coronary flow velocity reserve (rCVR) after successful coronary intervention has been related to microvascular impairment. However, the incidence of cardiac enzyme elevation as a surrogate marker of an underlying embolic myocardial injury in these cases has not been studied.

Methods and Results —A series of 55 consecutive patients with successful coronary stenting, periprocedural intracoronary Doppler analysis, and determination of creatine kinase (CK; upper limit of normal [ULN] for women 70 IU/L, for men 80 IU/L) and cardiac troponin T (cTnT; bedside test, threshold 0.1 ng/mL) before and 6, 12, and 24 hours after intervention were studied. Postprocedural rCVR was the only intracoronary Doppler parameter that independently correlated with cTnT ( r =−0.498, P <0.001) and CK outcome ( r =−0.406, P =0.002). Receiver operating characteristic analysis identified a postprocedural rCVR of 0.78 as the best discriminating value, with a sensitivity of 83.3% and 69.2% and a specificity of 79.1% and 76.2% for detection of cTnT and CK elevation, respectively. Stratified according to this cutoff value, the incidence of cTnT elevation was 52.6% in patients with (n=19) and 5.6% in patients without (n=36) a postprocedural rCVR <0.78 ( P <0.001), associated with a CK elevation >1 times the ULN in 36.8% and 5.6% ( P =0.005) of patients, respectively.

Conclusions —Cardiac marker elevation can frequently be found after coronary procedures that are associated with a persistent reduction of rCVR, indicating procedural embolization of atherothrombotic debris with microvascular impairment and myocardial injury as a potential underlying mechanism.

[Biochemical markers of ischemic and non-ischemic myocardial damage]

BACKGROUND

Biochemical markers have been an integrative part of non-invasive diagnostic strategies in cardiology for nearly 50 years, experiencing a renascence by the recently acknowledged prognostic potential of cardiac troponins in acute coronary syndromes.

DIAGNOSIS

According to the guidelines of the National Academy of Clinical Biochemistry and the International Federation of Clinical Chemistry cardiac troponin T and cardiac troponin I should be considered as the new "gold markers" of ischemic myocardial injury. One characteristic feature of these new markers is the improved diagnostic potential, reflected by the choice of two cut-off values to distinguish minor myocardial injury from acute myocardial infarction. In addition, cardiac troponins allow risk stratification in the clinical setting of acute coronary syndromes: approximately threefold higher mortality rate for patients with rest angina or ST segment elevation and cardiac troponin elevation on admission. Other indications for cardiac marker analysis are monitoring of therapeutic success in case of invasive and non-invasive reperfusion strategies and non-invasive diagnosis of non-ischemic myocardial injury (myocarditis, cardiac contusion and chemotherapy).

CONCLUSION

Biochemical cardiac markers are a useful tool in the diagnosis of both ischemic and non-ischemic myocardial injury. Among these, cardiac troponins seem to become the gold markers for the new millennium.

Intracoronary Doppler- and quantitative coronary angiography-derived predictors of major adverse cardiac events after stent implantation

BACKGROUND

Distal coronary flow velocity reserve (CVR) is significantly improved after a successful balloon angioplasty (PTCA). Furthermore, a postinterventional CVR >2.5 and a percent diameter stenosis (%DS) </=35% are predictive for a low incidence of major adverse cardiac events (MACE) at 6 months of 16%. Similar results are lacking for coronary stenting.

METHODS AND RESULTS

In 150 patients, baseline and hyperemic coronary flow velocities were recorded with a Doppler guidewire distal to the target lesion and in an unobstructed reference artery before and after PTCA, after stenting, and at 6 months. Distal CVR and relative CVR (CVR(rel)) were calculated. Logistic regression and receiver operating characteristic analyses were applied to determine prognostic cutoff values of CVR, CVR(rel), %DS, and minimal lumen diameter separately and in combination to predict MACE at 6 months. After stenting, CVR (2.96+/-0.87 versus 2.40+/-0.7; P:=0.001), CVR(rel) (1.02+/-0.24 versus 0.81+/-0.24; P:=0.001), and minimal lumen diameter (2.98+/-0.56 versus 2.11+/-0.74 mm; P:=0.001) were significantly higher than after PTCA. Thirty-three patients developed MACE. A postinterventional CVR(rel)>0.88 was the best single predictor of MACE, with an incidence of 6.8%, whereas the combination of a CVR(rel)>0.88 and a %DS </=11.2% predicted an incidence of MACE of 1.5%.

CONCLUSIONS

Measurement of CVR(rel) and %DS after stent implantation are best suitable to predict MACE at 6 months.

[Late stent thrombosis after intracoronary brachytherapy. A case report and review of the literature]

Intracoronary irradiation is currently the most promising approach to reduce restenosis after percutaneous transluminal coronary angioplasty. Meanwhile numerous data are available concerning efficacy and safety of this novel method. These data confirm the results of preclinical studies that reported a dramatic reduction of neo-intima proliferation and negative remodeling. However, the number of reports on an elevated incidence of late stent thrombosis (> 30 days post intervention) are increasing. It is commonly suggested that the delayed neo-intima formation within vascular stents is responsible for this new phenomenon. We report the case of a 48-year-old man who underwent coronary irradiation therapy after stent placement in a de-novo/restenotic lesion. Despite an explicit recommendation of a combined anti-aggregatory therapy consisting of ticlopidine and acetysalicylic acid for at least 6 months, ticlopidine was withdrawn after 4 weeks. Two weeks later, the patient was readmitted to an external hospital with an acute myocardial infarction and successfully treated with thrombolysis. The angiographic and intravascular control, which was conducted after another two weeks, showed absolutely no neointima formation within the implanted stent. Thus, a late thrombotic occlusion of the implanted stent appears most likely to be the cause underlying the myocardial infarction. This case underlines, together with other existing reports, the importance of a prolonged, combined anti-aggregatory therapy after stent placement and subsequent intracoronary irradiation.

Myocardial lactate release after intracoronary verapamil application in humans: acute effects of intracoronary verapamil on systemic and coronary hemodynamics, myocardial metabolism, and norepinephrine levels

Coronary and systemic hemodynamic effects of verapamil have been investigated previously in detail. The acute impact of intracoronary verapamil on coronary hemodynamics has, however, not been correlated to simultaneously changes in myocardial metabolism or norepinephrine levels in humans. After bolus application of 1 mg verapamil into the left coronary artery of 52 patients scheduled for routine coronary angiography, heart rate (HR) remained unchanged, whereas mean arterial blood pressure (MAP) decreased (93.8 +/- 14.9 mmHg to 85.1 +/- 13.7 mmHg, p = 0.001). Coronary blood flow (CBF), calculated from intracoronary Doppler measurements and quantitative coronary angiography, increased after verapamil administration (28.5 +/- 16.7 ml/min to 66.2 +/- 41.8 ml/min, p < 0.001), whereas coronary vascular resistance index (CVRI) decreased (1.43 +/- 0.92 to 0.46 +/- 0.23, p < 0.001). Blood samples, taken simultaneously from the aorta (Ao) and coronary sinus (CS) at baseline and at maximal flow velocity, showed an increase in norepinephrine concentrations in Ao (209 +/- 151 ng/l to 283 +/- 195 ng/l, p < 0.001) and CS (233 +/- 162 ng/l to 323 +/- 248 ng/l, p = 0.004). Myocardial metabolism of pyruvate and free fatty acids were not affected. Glucose release was augmented and initial lactate consumption changed to a net lactate release into the CS (Ao to CS differences: glucose: -1.92 +/- 9.9 mg/dl to -12.8 +/- 22.8 mg/dl, p < 0.001; lactate: 0.07 +/- 0.2 mmol/l to -0.08 +/- 0.3 mmol/l, p = 0.001). Similar results were obtained for the extraction ratios and flux of these metabolites. There was a weak correlation between the increase in CBF and lactate release into the CS. This is the first report of unexpected myocardial lactate release following intracoronary verapamil administration in humans. This lactate release was paralleled by an increased glucose release into the CS at an unchanged metabolism of free fatty acids and pyruvate. One explanation for this unexplained lactate release during increased coronary blood flow might be a wash out phenomenon of lactate from previous ischemic areas, other explanations might be the induction of paradox myocardial ischemia and/or a steal effect. Further studies are necessary to explain these unexpected findings of increased coronary flow and myocardial lactate release. Until reliable explanations are pending, studies using only lactate release as a marker of myocardial ischemia, without taken coronary and systemic hemodynamic parameters into account, should be interpreted with caution.

Dose-dependent effects of intracoronary verapamil on systemic and coronary hemodynamics

Calcium antagonists are used in interventional cardiology to prevent coronary vasoconstriction or to overcome the no-reflow phenomenon. The aim of the current study was to evaluate the dose-dependent effects of intracoronary verapamil on systemic and coronary hemodynamics. In 20 patients scheduled for routine coronary angiography, heart rate, blood pressure, and ECG recordings were recorded continuously and intracoronary flow velocity was obtained by intracoronary Doppler measurements in angiographically normal vessels. The cross-sectional area, measured by quantitative coronary angiography, allowed the calculation of coronary blood flow (CBF) and the coronary vascular resistance index (CVRI). Without premedication, increasing dosages of verapamil (0.01 mg, 0.1 mg, 1.0 mg, and 2.0 mg) were injected into the left coronary artery. Intracoronary verapamil administration led to a decrease in systemic blood pressure only after administration of 1.0 mg or 2.0 mg (change in mean arterial pressure: from 87.6 +/-14.6 mmHg to 80.1 +/- 14.9 mmHg and 78.5 +/- 13.9 mmHg, respectively; both P < 0.05) without a change in heart rate. Epicardial diameters of the left coronary artery increased only at dosages of 1.0 mg and 2.0 mg (from 2.14 +/- 0.4 mm to 2.22 +/- 0.3 mm, P < 0.01), whereas the coronary blood flow velocity increased significantly at the smallest dosage of 0.01 mg (from 19.9 +/- 8.7 cm/s to 33.2 +/- 14.9 cm/s, P < 0.001) and was further enhanced with increasing dosages. CBF increased and CVRI decreased at every dosage of verapamil compared with baseline values. CBF increased also after 0.1 mg (from 13.5 +/- 6.5 mL/min to 19.5 +/- 9.3 mL/min; P < 0.05), reaching a maximal effect after administration of 1.0 mg verapamil (26.3 +/- 16.1 mL/min, P < 0.05). Application of 2.0 mg did not further increase CBF compared with 1.0 mg. Intracoronary application of verapamil leads to a decrease in systemic blood pressure at higher dosages, whereas heart rate remains unchanged at any dosage. The maximal increase in coronary blood flow and decrease in vascular resistance can be reached by administration of 1.0 mg verapamil into the left coronary artery.

Nonsurgical retrieval of embolized coronary stents

Embolization of coronary stents before deployment is a rare but challenging complication of coronary stenting. Different methods for nonsurgical stent retrieval have been suggested. There were 20 cases (0.90%) of intracoronary stent embolization among 2,211 patients who underwent implantation of 4,066 stents. Twelve of 1,147 manually crimped stents (1.04%) and eight of 2,919 premounted stents were lost (0.27%, P < 0.01) during retraction of the delivery system, because the target lesion could not be either reached or crossed. Percutaneous retrieval was successfully carried out in 10 of 14 patients (71%) in whom retrieval was attempted. In 10 patients, stent retrieval was tried with 1.5-mm low-profile angioplasty balloon catheters (success in 7/10) and in seven cases with myocardial biopsy forceps or a gooseneck snare (success in 3/7). Three patients (15%) underwent urgent coronary artery bypass surgery after failed percutaneous retrieval, but their outcomes were fatal. In two patients, stents were compressed against the vessel wall by another stent, without compromising coronary blood flow. In two patients, a stent was lost to the periphery without clinical side effects; treatment was conservative in these cases. Embolization of stents before deployment is a rare but serious complication of coronary stenting, with hazardous potential for the patient. Manual mounting of stents is associated with a significantly higher risk of stent embolization. Stent retrieval from the coronary circulation with low-profile angioplasty balloon catheters is a readily available and technically familiar approach that has a relatively high success rate.

Percutaneous transluminal laser guide wire recanalization of chronic subclavian artery occlusion in symptomatic coronary-subclavian steal syndrome

Treatment of subclavian artery stenosis by percutaneous balloon angioplasty and adjunctive stent placement was shown to be safe and efficacious, but it may be limited in tight stenoses and long occlusions. We describe the case of a patient who experienced progressive angina pectoris associated with signs of cerebrovertebral insufficiency 9 yr after bypass surgery, including left internal mammary artery (LIMA) grafting to the left anterior descending coronary artery. Angiography showed reversed flow through the LIMA graft into the subclavian artery and a 4-cm occlusion beginning at the origin of the left subclavian artery, representing a rare coronary-subclavian steal syndrome. After a conventional approach failed, recanalization was performed successfully using laser guide wire angioplasty with adjunctive stent placement in a combined radial and femoral approach.

Enhanced epinephrine-induced platelet aggregation in individuals carrying the G protein beta3 subunit 825T allele

The 825T allele of a common C825T polymorphism in the gene encoding the beta3 subunit of heterotrimeric G proteins is associated with enhanced activation of pertussis toxin (PTX)-sensitive G proteins. We investigated responses of human platelets upon stimulation with epinephrine, which activates PTX-sensitive G proteins, and with agonists which activate additionally, or exclusively PTX-insensitive pathways. Slopes and maximum of the secondary aggregation were significantly enhanced in platelets from 825T allele carriers after epinephrine, and after combined epinephrine/ADP. This effect was more pronounced after inhibition of the cyclooxygenase-2 pathway by acetylsalicylic acid. This phenomenon appeared independent of platelet secretion, or inhibition of the adenylyl cyclase.

Immediate stent implantation versus conventional techniques for the treatment of abrupt vessel closure or symptomatic dissections after coronary balloon angioplasty

BACKGROUND

Coronary stenting was initially designed to treat a bailout scenario. Prospective randomized trials comparing stent implantation with standard techniques, including emergency coronary artery bypass grafting, are lacking. The aim of this trial was to test the superiority of immediate stent implantation compared with standard techniques for the treatment of abrupt or threatening closure after coronary balloon angioplasty.

METHODS

In a prospective trial, 100 patients with abrupt vessel closure or symptomatic dissections causing objective signs of ischemia were randomly assigned to treatment with immediate placement of stents (n = 51) versus standard techniques such as prolonged dilatation or emergency bypass surgery (n = 49). The primary end point was the achievement of successful stabilization not requiring crossover to the other study group. Secondary end points included event-free survival and restenosis.

RESULTS

Successful stabilization was achieved in 94% of patients in the stent group compared with 78% of patients in the standard treatment group (P =.038). Two patients died in each group, and there was a trend toward a higher incidence of myocardial infarction (16% vs 8%; P =.163) and a significantly increased creatine phosphokinase level (245 IU/L [95% confidence interval, 217-265 IU/L] vs 179 IU/L [confidence interval 140-212 IU/L]; P =.0002) in the standard treatment group. Event-free survival after 250 days was 72% in the stent group compared with 29% in the standard treatment group (P =.001). The angiographic restenosis rate was 30% in the stent group versus 59% in the standard treatment group (P =.01).

CONCLUSIONS

Immediate stenting, if technically feasible, shows superior short- and long-term results compared with standard treatment options.

Size of emptied plaque cavity following spontaneous rupture is related to coronary dimensions, not to the degree of lumen narrowing. A study with intravascular ultrasound in vivo

OBJECTIVE

To identify any potential relations between the size of an emptied plaque cavity and the remodelling pattern, plaque or vessel dimensions, lumen narrowing, and other ultrasonic lesion characteristics.

DESIGN

Intravascular ultrasound was used to examine prospectively 51 ruptured ulcerated coronary plaques. Cross sectional area measurements comprised lumen, vessel, plaque, and emptied plaque cavity. Lumen narrowing was calculated as 1 - (lesion lumen area/reference lumen area) x 100%. A remodelling index was calculated as lesion vessel area/reference vessel area, and plaques were divided into those with values > 1.05 (group A) and </= 1.05 (group B).

RESULTS

Of the total of 51 plaques, 36 (71%) were assigned to group A and 15 (29%) to group B. In neither group was there a significant difference in reference dimensions and lumen narrowing. However, lesion vessel (mean (SD): 22.6 (8.1) mm(2) v 17. 5 (4.3) mm(2); p = 0.006) and plaque areas (15.8 (6.2) mm(2) v 12.8 (3.2) mm(2); p = 0.03) were greater in group A than in group B. The cavity inside the plaque was larger in group A than in group B (2.8 (1.6) mm(2) v 1.8 (0.9) mm(2); p = 0.007) and showed a positive linear relation with lesion and reference vessel size (r = 0.58 and 0.56, respectively; p < 0.001), but not with lumen narrowing.

CONCLUSIONS

The size of the emptied cavity inside ruptured plaques is on average larger in lesions with adaptive vascular remodelling, and shows a linear relation with lesion plaque and vessel size and with the reference dimensions, but not with the degree of lumen narrowing.

Total occlusion trial with angioplasty by using laser guidewire. The TOTAL trial

AIMS

A randomized trial was performed to assess the safety and efficacy of a laser guidewire, in the treatment of chronic coronary occlusions.

METHODS AND RESULTS

In 18 European centres, 303 patients with a chronic coronary occlusion were randomized to treatment with either the laser guidewire (n=144) or conventional guidewires (mechanical guidewire, n=159). The primary end-point of the study was treatment success, defined as reaching the true lumen distal to the occlusion by the allocated wire within 30 min of fluoroscopic time: laser guidewire vs mechanical guidewire; 52.8% (n=76) vs 47.2% (n=75), P=0.33. Serious adverse events following the initial guidewire attempt were 0% (laser guidewire) and 0.6% (mechanical guidewire), respectively. Angioplasty (performed following successful guidewire crossing) was successful in 179 patients (91%, laser guidewire n=79, mechanical guidewire n=100), followed by stent implantation in 149 (79%). At the 6-month angiographic follow-up, the difference in binary restenosis rate (laser guidewire vs mechanical guidewire; 45.5% vs 38.3 %, P=0.72) or reocclusion rate (25.8% vs 16.1%, P=0.15) did not reach statistical significance. At 1, 6 and 12 months, angina and event-free survival were 69%, 35% and 24% (laser guidewire) vs 74%, 40% and 31% (mechanical guidewire).

CONCLUSION

Although laser guidewire technology was safe, the increase in crossing success did not reach statistical significance.

A randomized comparison of balloon angioplasty versus rotational atherectomy in complex coronary lesions (COBRA study)

AIMS

Rotablation is a widely used technique for the treatment of complex coronary artery lesions but is so far only poorly supported by controlled studies. The Comparison of Balloon-Angioplasty versus Rotational Atherectomy study (COBRA) is a multicentre, prospective, randomized trial to compare short- and long-term effects of percutaneous transluminal coronary angioplasty (PTCA) and rotablation in patients with angiographically pre-defined complex coronary artery lesions.

METHODS AND RESULTS

At seven clinical sites 502 patients with pre-defined complex coronary artery lesions were assigned to either PTCA (n=250) or rotablation (n=252). Primary end-points were procedural success, 6-month restenosis rates in the treated segments, and major cardiac events during follow-up. Procedural success was achieved in 78% (PTCA), and 85% (rotablation) (P=0.038) of cases. Crossover from PTCA to rotablation was 4% and 10% vice versa (P=0.019). There was no difference between PTCA and rotablation with respect to procedure-related complications such as Q wave infarctions (2.4% each), emergency bypass surgery (1.2% versus 2.4%), and death (1.6% versus 0.4%). However, more stents were required after PTCA (14.9% versus 6.4%, P<0.002), predominantly for bailout or unsatisfactory results. Including bail-out stents as an end-point, the procedural success rates were 73% for angioplasty and 84% for rotablation (P=0.006). At 6 months, symptomatic outcome, target vessel reinterventions and restenosis rates (PTCA 51% versus rotablation 49%, P=0.33) were not different.

CONCLUSION

Complex coronary artery lesions can be treated with a high level of success and low complication rates either by PTCA with adjunctive stenting or rotablation. The long-term clinical and angiographic outcome is comparable.

[Electromechanically controlled versus roengenologically guided percutaneous transluminal laser myocardial revascularization]

Transmyocardial laser revascularization is a modern therapeutic concept for patients with end-stage coronary artery disease not eligible for bypass surgery, percutaneous coronary interventions or heart transplantation. Although the principal idea of creating additional myocardial perfusion from the cavum of the left ventricle was derived from observations in reptile hearts, histological investigations suggest that channel patency is not the underlying mechanism for improved clinical symptoms. Sympathetic denervation and angioneogenesis may be additional explanations for improvement of angina and stress tolerance. The first experiences with transmyocardial laser revascularization were made using a surgical approach. Two randomized multicenter trials could show a significant improvement in angina and stress tolerance 12 months after creating channels using laser technique. While these results were obtained by performing thoracotomy, catheter-based systems have been designed for a less invasive approach of this technique. A further advantage of these new systems is that regions like the septum can be treated which are not eligible for a surgical approach. Using percutaneous transluminal catheter-based systems channels of up to 6 mm length can be created. Beside the fluoroscopic guided creation of myocardial channels a new mapping system has been applied using electromechanical features of viable myocardial tissue. This system is based on the observation that endocardial electrograms recorded from an infarcted area are characterized by very low amplitude and fractionated morphology. This system allows online mapping of viable myocardium and provides spatial, electrical, and mechanical information of the myocardium. This method of electromechanical mapping highly correlates with results obtained from myocardial perfusion scans. Recent preliminary clinical trials demonstrated that catheter-based creation of myocardial channels is a feasible and successful alternative to the surgical laser revascularization. Also with this approach a significant improvement in angina and stress tolerance can be achieved. The results of the PACIFIC study, the first randomized multicenter study using percutaneous transluminal laser revascularization, demonstrates that after 3 and 6 months more than half of the patients presented improved angina of at least 1 Canadian-Cardiovascular-Society class. Whether electromechanical guided myocardial laser revascularization is more efficient than fluoroscopic guided has not been proven yet. Further studies will have to evaluate this issue.

[Transluminal exclusion of a subclavian artery aneurysm with stent-graft implantation]

In a 73 year-old male patient with generalized atherosclerosis, known infrarenal abdominal aortic aneurysm, renal artery stenosis, and coronary artery disease, an aneurysm of the proximal left subclavian artery was successfully excluded by implantation of a JOSTENT-Peripheral stent graft. Angiographic follow up after 6 and 12 months showed an excellent outcome with complete exclusion of the aneurysm. Intravascular ultrasound showed no neo-intimal hyperplasia within the stent. A computed tomography revealed complete thrombosis of the aneurysm.

Safety of intracoronary Doppler flow measurement

BACKGROUND

With the introduction of Doppler-tipped guide wires, intracoronary Doppler flow measurement has been increasingly accepted as an additional diagnostic approach in the catheterization laboratory. However, the safety of intracoronary Doppler flow measurement has not been well-investigated. The purpose of our study was to evaluate the safety of intracoronary Doppler flow measurement using the Doppler FloWire (Cardiometrics, Mountain View, Calif).

METHODS AND RESULTS

A total of 906 patients were examined by intracoronary Doppler with a 0.014-inch or an 0.018-inch Doppler FloWire. For coronary flow reserve measurement, intracoronary injection of adenosine or papaverine was used. Of the patients studied, 77 were cardiac transplant recipients and 829 were patients who had not received a transplant, of whom 617 had undergone diagnostic coronary procedures and 212 had coronary interventions. In 27 (2.98%) of 906 patients adverse cardiac events were observed. Fifteen (1.66%) of 906 patients had severe transient bradycardia develop (asystole or second- to third-degree atrioventricular block) after intracoronary administration of adenosine, 14 of which occurred in the right coronary artery and 1 in the left anterior descending artery. Nine (0.99%) of 906 patients had coronary spasm during the passage of the Doppler wire (5 in the right coronary artery, 4 in the left anterior descending artery). Two (0.22%) of 906 patients had ventricular fibrillation during the procedure. Hypotension with bradycardia and ventricular extrasystole each occurred in 1 (0.11%) of 906 patients. The incidence of complication was significantly higher in transplant recipients than in patients who underwent either diagnostic or interventional procedures (12.99% vs 2.43% vs 0.94%, P <.001). The Doppler measurements in the right coronary artery were associated with a higher incidence of complications, especially bradycardia, compared with the left anterior descending and the left circumflex arteries (right coronary, 5.87% vs left anterior descending, 1.05% vs left circumflex, 0.17%; P <.001). All complications were cured medically.

CONCLUSION

Intracoronary Doppler flow measurement with Doppler wires and intracoronary administration of adenosine is a safe method. However, severe complications such as bradycardia and coronary spasm can occur. Attention should be paid to the examination of the right coronary artery, especially in heart transplant recipients.