Transcatheter tricuspid valve repair: early experience in the Netherlands.

BACKGROUND: Symptomatic tricuspid regurgitation (TR) is increasingly prevalent and impairs quality of life and survival, despite medical treatment. Transcatheter tricuspid valve repair (TTVR) has recently become available as a treatment option for patients not eligible for tricuspid valve surgery. In this study we describe the early experience with TTVR in the Netherlands. METHODS: All consecutive patients scheduled for TTVR in two tertiary hospitals were included in the current study. Patients were symptomatic and had severe functional TR. TTVR was performed either with the MitraClip (off-label use) or dedicated TriClip delivery system and device. Procedural success was defined as achievement of clip implantation, TR reduction ≥ 1 grade and no need for re-do surgical or transcatheter intervention. Clinical improvement was evaluated after 4 weeks. RESULTS: Twenty-one patients (median age 78 years, 33% male, 95% New York Heart Association class ≥ 3, 100% history of atrial fibrillation) underwent TTVR. Procedural success was achieved in 16 patients, of whom 15 reported symptomatic improvement (New York Heart Association class 1 or 2). There was no in-hospital mortality and no major complications occurred. Baseline glomerular filtration rate and TR coaptation gap size were associated with procedural success. CONCLUSION: The current study showed that TTVR seems a promising treatment option for patients with severe functional TR deemed high risk for surgery. Successful TR reduction is most likely in patients with limited coaptation gap size and strongly determines clinical benefit. Adequate patient selection and timing of treatment seem essential for an optimal patient outcome.

Prognostic implications of resting distal coronary-to-aortic pressure ratio compared with fractional flow reserve: a 10-year follow-up study after deferral of revascularisation.

INTRODUCTION: The distal coronary-to-aortic pressure ratio (Pd/Pa) is a non-hyperaemic physiological index to assess the functional severity of coronary stenoses. Studies comparing Pd/Pa with fractional flow reserve (FFR) show superior diagnostic efficiency for myocardial ischaemia. Nevertheless, a direct comparison regarding long-term clinical outcomes is still not available. The present observational study compared the prognostic value of Pd/Pa and FFR for major adverse cardiac events (MACE) during a 10-year follow-up period after deferral of revascularisation. METHODS: Between April 1997 and September 2006, we evaluated 154 coronary stenoses (154 patients) in which revascularisation was deferred with intracoronary pressure and flow measurements during the resting and hyperaemic state. Long-term follow-up (median: 11.8 years) was performed to document the occurrence of MACE, defined as a composite of cardiac death, myocardial infarction and target vessel revascularisation. RESULTS: The study population comprised angiographically intermediate coronary stenoses, with a mean diameter stenosis of 53 ± 8%, and intermediate physiological severity with a median FFR of 0.82 (Q1, Q3: 0.76, 0.88). The association of Pd/Pa with long-term MACE was similar to that of FFR [FFR-standardised hazard ratio (sHR): 0.77, 95% confidence interval (CI): 0.61-0.98; Pd/Pa-sHR: 0.80, 95% CI: 0.67-0.96]. In the presence of disagreement between Pd/Pa and FFR, normal Pd/Pa was generally associated with high coronary flow reserve (CFR) and a favourable clinical outcome, whereas abnormal Pd/Pa was generally associated with CFR around the ischaemic cut-point and an impaired clinical outcome, regardless of the accompanying FFR value. CONCLUSION: The present study suggests that Pd/Pa provides at least equivalent prognostic value compared with FFR. When Pd/Pa disagreed with FFR, the baseline index conferred superior prognostic value in this study population.

The Absorb bioresorbable vascular scaffold in real-world practice: long-term follow-up of the AMC Single Centre Real World PCI Registry.

BACKGROUND: Bioresorbable scaffolds have been introduced to overcome the shortcomings of drug-eluting stents. Higher rates of device thrombosis, however, have been reported up to 3 years after implantation of the Absorb bioresorbable vascular scaffold (BVS). In the current article, we therefore report long-term clinical outcomes of the AMC Absorb Registry. METHODS AND RESULTS: In the AMC Absorb Registry, all patients who underwent a percutaneous coronary intervention with Absorb BVS implantation between 30 August 2012 and 5 August 2013 at the Amsterdam University Medical Centre-Academic Medical Centre were included. The composite endpoint of this analysis was target-vessel failure (TVF). The median follow-up of the study cohort of the AMC Absorb Registry was 1534 days. At the time of the cross-sectional data sweep the clinical status at 4 years was known in 124 of 135 patients (91.9%). At long-term follow-up, the composite endpoint of TVF had occurred in 27 patients. The 4­year Kaplan-Meier estimate of TVF was 19.8%. At 4 years cardiac death had occurred in 4 patients (3.2%) and target-vessel myocardial infarction in 9 (6.9%) patients. Definite scaffold thrombosis occurred in 5 (3.8%) patients. We found 1 case of very late scaffold thrombosis that occurred at 911 days after device implantation in a patient who was not on dual anti-platelet therapy. CONCLUSION: In a patient population reflecting routine clinical practice, we found that cases of TVF continued to accrue beyond 2 years after Absorb BVS implantation.

Acute alterations in glucose homeostasis impact coronary microvascular function in patients presenting with ST-segment elevation myocardial infarction.

BACKGROUND: Microvascular dysfunction in the setting of ST-segment myocardial infarction (STEMI) is thought to be related to stress-related metabolic changes, including acute glucose intolerance. The aim of this study was to assess the relationship between admission glucose levels and microvascular function in non-diabetic STEMI patients. METHODS: 92 consecutive patients with a first anterior-wall STEMI treated with primary percutaneous coronary intervention (PPCI) were enrolled. Blood glucose levels were determined immediately prior to PPCI. After successful PPCI, at 1­week and 6­month follow-up, Doppler flow was measured in culprit and reference coronary arteries to calculate coronary flow velocity reserve (CFVR), baseline (BMR) and hyperaemic (HMR) microvascular resistance. RESULTS: The median admission glucose was 8.3 (7.2-9.6) mmol/l respectively 149.4 mg/dl [129.6-172.8] and was significantly associated with peak troponin T (standardised beta coefficient [std beta] = 0.281; p = 0.043). Multivariate analysis revealed that increasing glucose levels were significantly associated with a decrease in reference vessel CFVR (std beta = -0.313; p = 0.002), dictated by an increase in rest average peak velocity (APV) (std beta = 0.216; p = 0.033), due to a decreasing BMR (std beta = -0.225; p = 0.038) in the acute setting after PPCI. These associations disappeared at follow-up. These associations were not found for the infarct-related artery. CONCLUSION: Elevated admission glucose levels are associated with impaired microvascular function assessed directly after PPCI in first anterior-wall STEMI. This influence of glucose levels is an acute phenomenon and contributes to microvascular dysfunction through alterations in resting flow and baseline microvascular resistance.

Early mobilisation after transfemoral transcatheter aortic valve implantation: results of the MobiTAVI trial.

BACKGROUND: Immobilisation of patients after transfemoral transcatheter aortic valve implantation (TF-TAVI) is the standard of care, mostly to prevent vascular complications. However, immobilisation may increase post-operative complications such as delirium and infections. In this trial, we determine whether it is feasible and safe to implement early ambulation after TF-TAVI. METHODS: We prospectively included TF-TAVI patients from 2016 to 2018. Patients were assessed for eligibility using our strict safety protocol and were allocated (based on the time at which the procedure ended) to the EARLY or REGULAR group. RESULTS: A total of 150 patients (49%) were deemed eligible for early mobilisation, of which 73 were allocated to the EARLY group and 77 to the REGULAR group. The overall population had a mean age of 80 years, 48% were male with a Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) score of 3.8 ± 1.8. Time to mobilisation was 4 h 49 min ± 31 min in the EARLY group versus 20 h 7 min ± 3 h 6 min in the REGULAR group (p < 0.0001). There were no differences regarding the primary endpoint. No major vascular complications occurred and a similar incidence of minor vascular complications was seen in both groups (4/73 [5.5%] vs 6/77 [7.8%], p = 0.570). The incidence of the combined secondary endpoint was lower in the EARLY group (p = 0.034), with a numerically lower incidence for all individual outcomes (delirium, infections, pain and unplanned urinary catheter use). CONCLUSION: Early mobilisation (ambulation 4-6 h post-procedure) of TF-TAVI patients is feasible and safe. Early ambulation decreases the combined incidence of delirium, infections, pain and unplanned urinary catheter use, and its adoption into contemporary TAVI practice may therefore be beneficial.

Transcatheter aortic valve replacement alters ascending aortic blood flow and wall shear stress patterns: A 4D flow MRI comparison with age-matched, elderly controls.

BACKGROUND: With the implementation of transcatheter aortic valve replacement (TAVR) in lower-risk patients, evaluation of blood flow characteristics and the effect of TAVR on aortic dilatation becomes of considerable interest. We employed 4D flow MRI in the ascending aorta of patients after TAVR to assess wall shear stress (WSS) and compare blood flow patterns with surgical aortic valve replacement (SAVR) and age- and gender-matched controls. METHODS: Fourteen post-TAVR patients and ten age- and gender-matched controls underwent kt-PCA accelerated 4D flow MRI of the thoracic aorta at 3.0 Tesla. Velocity and wall shear stress was compared between the two groups. In addition, aortic flow eccentricity and displacement was assessed and compared between TAVR patients, controls and 14 SAVR patients recruited as part of an earlier study. RESULTS: Compared to controls, abnormally elevated WSS was present in 30±10% of the ascending aortic wall in TAVR patients. Increased WSS was present along the posterior mid-ascending aorta and the anterior distal-ascending aorta in all TAVR patients. TAVR results in eccentric and displaced flow in the mid- and distal-ascending aorta, whereas blood flow displacement in SAVR patients occurs only in the distal-ascending aorta. CONCLUSION: This study shows that TAVR results in increased blood flow velocity and WSS in the ascending aorta compared to age- and gender-matched elderly controls. This finding warrants longitudinal assessment of aortic dilatation after TAVR in the era of potential TAVR in lower-risk patients. Additionally, TAVR results in altered blood flow eccentricity and displacement in the mid- and distal-ascending aorta, whereas SAVR only results in altered blood flow eccentricity and displacement in the distal-ascending aorta. KEY POINTS: • TAVR results in increased blood flow velocity and WSS in the ascending aorta. • Longitudinal assessment of aortic dilatation after TAVR is warranted in the era of potential TAVR in lower-risk patients. • Both TAVR and SAVR result in altered blood flow patterns in the ascending aorta when compared to age-matched controls.

Cardiology fellows-in-training are exposed to relatively high levels of radiation in the cath lab compared with staff interventional cardiologists-insights from the RECAP trial.

BACKGROUND: Interventional cardiologists are inevitably exposed to low-dose radiation, and consequently are at risk for radiation induced diseases like cataract and left-sided brain tumours. Operator behaviour may possibly be the largest influencer on radiation exposure. We hypothesised that awareness regarding radiation exposure grows as skill and the general experience in the catheterization laboratory increase. OBJECTIVES: In this study we determined the difference in the relative radiation exposure of staff interventional cardiologists compared with cardiology fellows-in-training. METHODS: During this prospective trial the operator's radiation exposure (E in µSv) was measured at chest height during 766 diagnostic catheterisations and percutaneous coronary interventions. Also, the patient exposure (DAP in mGy·cm2), representing the amount of radiation administered by the operator per procedure, was collected. The primary outcome of this study was the difference in relative exposure between staff interventional cardiologists versus cardiology fellows-in-training (E/DAP). RESULTS: From January to May 2017, staff interventional cardiologists performed 637 procedures and cardiology fellows-in-training 129 procedures. The performance of relatively complex procedures by staff interventional cardiologists resulted in a 74% higher use of radiation compared with fellows-in-training. Consequently, staff interventional cardiologists were exposed to 50% higher levels of actual radiation exposure. However, when correcting for the complexity of the procedure, by comparing the relative operator exposure (E/DAP), fellows-in-training were exposed to a 34% higher relative exposure compared with staff interventional cardiologists (p = 0.025). CONCLUSIONS: In the current study, when corrected for complexity, cardiology fellows-in-training were exposed to significantly higher radiation levels than staff interventional cardiologists during catheterisation procedures.

Five-year clinical follow-up of the STENTYS self-apposing stent in complex coronary anatomy: a single-centre experience with report of specific angiographic indications.

OBJECTIVES: We sought to investigate angiographic indications for the use of the STENTYS technique and evaluated the long-term safety and clinical efficacy of the stent. BACKGROUND: Coronary lesions involving complex anatomy, including aneurysmatic, ectatic, or tapered vessel segments often carry a substantial risk of stent malapposition. The self-apposing stent technique may reduce the risk of stent malapposition and therefore improve clinical outcomes. METHODS: A total of 120 consecutive patients treated with the STENTYS stent were included (drug-eluting stent (DES) n = 101, bare-metal stent (BMS) n = 19). All lesions were scored for angiographic indications for the STENTYS stent, including aneurysms, ectasias, tapering, absolute diameters, bifurcation lesions, and saphenous vein grafts. Off-line quantitative coronary angiography analyses were performed pre-procedure and post-procedure. Five years follow-up was obtained including cardiac death, target vessel myocardial infarction (TV-MI), target vessel revascularisation, stent thrombosis, and the composite endpoint target vessel failure (cardiac death, TV-MI and target vessel revascularisation). RESULTS: Angiographic indications for STENTYS use were aneurysm (30%), ectasia (19%), tapering (27%), bifurcation lesions (8%), and saphenous vein graft lesions (16%) and absolute diameters (22%). Mean maximal diameter was 4.51 ± 0.99 mm. At 5­year follow-up target vessel failure rates were 24.1% in the total cohort (DES 22.8% vs. BMS 33%, p = 0.26). Definite stent thrombosis rate was 3.8% at 5­year follow-up in this cohort with complex and high-risk lesions (DES 4.5% vs. BMS 0%, p = 0.39). CONCLUSIONS: Angiographic indications for the use of the self-apposing stent were complex lesions with atypical coronary anatomy. Our data showed reasonable stent thrombosis rates at 5­year follow-up, considering the high-risk lesion characteristics.

Trends in patient characteristics and clinical outcome over 8 years of transcatheter aortic valve implantation.

AIM: In the evolving field of transcatheter aortic valve implantations (TAVI) we aimed to gain insight into trends in patient and procedural characteristics as well as clinical outcome over an 8­year period in a real-world TAVI population. METHODS: We performed a single-centre retrospective analysis of 1,011 consecutive patients in a prospectively acquired database. We divided the cohort into tertiles of 337 patients; first interval: January 2009-March 2013, second interval: March 2013-March 2015, third interval: March 2015-October 2016. RESULTS: Over time, a clear shift in patient selection was noticeable towards lower surgical risks including Society of Thoracic Surgeons predicted risk of mortality score and comorbidity. The frequency of transfemoral TAVI increased (from 66.5 to 77.4%, p = 0.0015). Device success improved (from 62.0 to 91.5%, p < 0.0001) as did the frequency of symptomatic relief (≥1 New York Heart Association class difference) (from 73.8 to 87.1%, p = 0.00025). Complication rates decreased, including in-hospital stroke (from 5.0 to 2.1%, p = 0.033) and pacemaker implantations (from 10.1 to 5.9%, p = 0.033). Thirty-day mortality decreased (from 11.0 to 2.4%, p < 0.0001); after adjustment for patient characteristics, a mortality-risk reduction of 72% was observed (adjusted hazard ratio [HR]: 0.28, 95% confidence interval [CI]: 0.13-0.62). One-year mortality rates decreased (from 23.4 to 11.4%), but this was no longer significant after a landmark point was set at 30 days (mortality from 31 days until 1 year) (adjusted HR: 0.69, 95% CI: 0.41-1.16, p = 0.16). CONCLUSION: A clear shift towards a lower-risk TAVI population and improved clinical outcome was observed over an 8­year period. Survival after TAVI improved impressively, mainly as a consequence of decreased 30-day mortality.

Pre-hospital management, procedural performance and outcomes for primary percutaneous coronary intervention in ST-elevation myocardial infarction in the Netherlands: Insights from the Dutch cohort of the APPOSITION-III trial.

AIM: The aim of this study was to achieve useful insights into pre-hospital management and procedural performance for ST-elevation myocardial infarction (STEMI) in the Netherlands by extrapolating patient characteristics, and procedural and clinical outcomes of the Dutch patient cohort from the APPOSITION-III trial. METHODS: This is a retrospective analysis from the APPOSITION-III trial with respect to the geographical borders of STEMI management. The APPOSITION-III trial was a European registry for the use of the STENTYS self-expandable stent in STEMI patients undergoing primary percutaneous coronary intervention (PPCI). 965 Patients were enrolled mainly in the Netherlands (n = 420, 43.5 % of the overall study population), Germany (n = 165) and France (n = 131). The data from the Dutch cohort were compared with both the overall study population, and the French and German cohorts, respectively, as well as the European Society of Cardiology (ESC) STEMI guidelines. RESULTS: In this trial there was a wide inter-country variation on symptom-to-balloon time, 165 minutes (120-318) in the Netherlands, 270 minutes (180-650) in Germany and 360 minutes (120-480) in France, respectively. In general, a preload of dual antiplatelet therapy (DAPT) combined with heparin was more often performed in the Dutch and French cohort than in the German cohort. DAPT at discharge was high across the whole APPOSITION-III population. No important differences were seen between the different groups according to the endpoints major adverse cardiac event and stent thrombosis. CONCLUSION: In the Dutch cohort of an European multicentre STEMI study (APPOSITION-III trial), the performance in terms of symptom-to-balloon time, and pre-, peri- and post-procedural medical treatment is in line with the recommendations of ESC STEMI guidelines.

Coronary microcirculatory dysfunction is associated with left ventricular dysfunction during follow-up after STEMI.

BACKGROUND: Coronary microvascular resistance is increased after primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI), which may be related in part to changed left ventricular (LV) dynamics. Therefore we studied the coronary microcirculation in relation to systolic and diastolic LV function after STEMI. METHODS: The study cohort consisted of 12 consecutive patients, all treated with primary PCI for a first anterior wall STEMI. At 4 months, we assessed pressure-volume loops. Subsequently, we measured intracoronary pressure and flow velocity and calculated coronary microvascular resistance. Infarct size and LV mass were assessed using magnetic resonance imaging. RESULTS: Patients with an impaired systolic LV function due to a larger myocardial infarction showed a higher baseline average peak flow velocity (APV) than the other patients (26 ± 7 versus 17 ± 5 cm/s, p = 0.003, respectively), and showed an impaired variable microvascular resistance index (2.1 ± 1.0 versus 4.1 ± 1.3 mmHg cm(-1)∙s(-1), p = 0.003, respectively). Impaired diastolic relaxation time was inversely correlated with hyperaemic APV (r = -0.56, p = 0.003) and positively correlated with hyperaemic microvascular resistance (r = 0.48, p = 0.01). LV dilatation was associated with a reduced variable microvascular resistance index (r = 0.78, p = 0.006). CONCLUSION: A larger anterior myocardial infarction results in impaired LV performance associated with reduced coronary microvascular resistance variability, in particular due to higher coronary blood flow at baseline in these compromised left ventricles.

Percutaneous left ventricular partitioning device for chronic heart failure.

We report the first implantation of a percutaneous left ventricular partitioning device in the Netherlands. This device is developed for patients with chronic heart failure due to a left ventricular apical aneurysm caused by an anterior myocardial infarction.

Can stress echocardiography identify patients who will benefit from percutaneous mitral valve repair?

The aim of the current study was to investigate whether stress echocardiography improves selection of patients who might have clinical benefit from percutaneous mitral valve repair with the MitraClip. In total, 39 patients selected for MitraClip implantation underwent preprocedural low-dose stress (dobutamine or handgrip) echocardiography from which stroke volume, ejection fraction and MR grade were measured. Outcome after MitraClip implantation was determined by New York Heart Association classification and Quality of Life questionnaires. Clinical benefit from MitraClip treatment was defined as survival and NYHA class I-II at 6 months follow-up. In total, 36 patients with a technically successful procedure were included in the analysis (mean age 79 ± 8 years, 47% male, 50% functional MR). Clinical benefit was achieved in 18 patients. All seven patients with MR decreasing during stress remained in NYHA III-IV or died within 6 months, while 62% (18 out of 29) of the patients with stable or increased MR during stress had clinical benefit (p = 0.008). Significant increase in Quality of Life on 4/8 subscales of the RAND Short Form-36 questionnaire was observed: Physical Functioning (p < 0.001), Social Functioning (p < 0.001), Mental Health (p = 0.022) and Vitality (p = 0.026) was seen in patients with an increase in stroke volume during stress echocardiography. Patients with a decreased MR during preprocedural stress echocardiography remained more symptomatic than patients with a stable or increased MR during stress. Stress echocardiography may support patient selection for percutaneous mitral valve repair.

Long-term prognostic value of CFVR and FFR versus perfusion scintigraphy in patients with multivessel disease.

OBJECTIVE: In this multicentre study, we investigated the long-term prognostic value of intracoronary derived haemodynamic parameters compared with the results of myocardial perfusion scintigraphy (MPS). METHODS: Patients (n=191) who were referred for angioplasty of a severe lesion in the presence of an intermediate lesion in another coronary artery were included. MPS was performed to determine the presence of reversible perfusion defects in the area of the intermediate lesion. Coronary flow velocity reserve (CFVR), and additionally fractional flow reserve (FFR; n=129), were determined distal to the intermediate lesion; CFVR >/=2.0 and FFR >/=0.75 were considered negative. RESULTS: In total 67 events occurred in 49 patients (3 deaths, 9 MI, 9 CABG, 46 PTCA) during a mean of 793 days follow-up. Event-free survival was 63% for MPS, 79% for CFVR, and 79% for FFR if a negative test result was obtained. The relative risk was 1.2 (not significant) for MPS, 2.2 (p=0.001) for CFVR, and 2.4 (p=0.004) for FFR. CONCLUSION: Selective evaluation of an intermediate lesion using CFVR or FFR allows more adequate risk stratification in patients with multivessel disease than MPS. A CFVR <2.0 or a FFR <0.75 was associated with a significant increase of the occurrence of cardiac events during long-term follow-up, predominantly associated with revascularisation. (Neth Heart J 2007;15:369-74.).

Colocalisation of intraplaque C reactive protein, complement, oxidised low density lipoprotein, and macrophages in stable and unstable angina and acute myocardial infarction.

BACKGROUND: C reactive protein (CRP), an important serum marker of atherosclerotic vascular disease, has recently been reported to be active inside human atherosclerotic plaques. AIMS: To investigate the simultaneous presence of macrophages, CRP, membrane attack complex C5b-9 (MAC), and oxidised low density lipoprotein (oxLDL) in atherectomy specimens from patients with different coronary syndromes. METHODS: In total, 54 patients with stable angina (SA; n = 21), unstable angina (UA; n = 15), and myocardial infarction (MI; n = 18) underwent directional coronary atherectomy for coronary lesions. Cryostat sections of atherosclerotic plaques were immunohistochemically stained with monoclonal antibodies: anti-CD68 (macrophages), anti-5G4 (CRP), aE11 (MAC), and 12E7 (oxLDL). Immunopositive areas were evaluated in relation to fibrous and neointima tissues, atheroma, and media. Quantitative analysis was performed using image cytometry with systematic random sampling (percentage immunopositive/total tissue area). RESULTS: Macrophages, CRP, MAC, and oxLDL were simultaneously present in a higher proportion of fibrous tissue and atheroma of atherectomy specimens from patients with UA and MI compared with SA (p<0.05). Quantitative analysis showed significantly higher mean percentages of macrophages in plaques from patients with MI (44%) than UA (30%; p<0.01) and SA (20%; p<0.001). Significantly higher mean percentages of CRP were also seen in MI (25%) and UA (25%) compared with SA (12%; p<0.05). CONCLUSIONS: The presence of CRP, complement, and oxLDL in a high proportion of plaque tissue from patients with unstable coronary artery disease implies that these surrogate markers have important proinflammatory effects inside atherosclerotic plaques. This may increase vulnerability to plaque rupture and thrombosis, with subsequent clinical sequelae.

Comparison of collateral vascular responses in the donor and recipient coronary artery during transient coronary occlusion assessed by intracoronary blood flow velocity analysis in patients.

OBJECTIVES: This study was designed to evaluate the hemodynamic variables of the collateral circulation during acute coronary occlusion. BACKGROUND: There is limited information on the physiology of the collateral circulation in coronary artery disease. METHODS: Angiography of the contralateral donor artery was performed before and during balloon coronary occlusion in 57 patients with one-vessel disease. Recruitable collateral flow was assessed during coronary occlusion by blood flow analysis of the contralateral donor artery (n = 19) or the ipsilateral recipient artery (n = 15), or both (n = 23), using a Doppler catheter or guide wire. Ischemia was evaluated by the ST segment shift (> or = 0.1 mV) on a 12-lead electrocardiogram at 1 min of coronary occlusion. RESULTS: The presence (n = 39), compared with the absence (n = 18), of recruitable collateral vessels was associated with an increase of blood flow velocity in the donor artery (20 +/- 19% vs. 4.8 +/- 5.9% [mean +/- SD], p = 0.003) and the recipient artery (velocity integral 7.2 +/- 5.5 vs. 2.8 +/- 2.2 cm, p = 0.02) related to a reduced relative collateral vascular resistance (9.2 +/- 10 vs. 20 +/- 11, p = 0.003). Collateral flow in the donor artery yielded a similar predictive value for recruitability of collateral vessels as collateral flow determined in the recipient artery or the coronary wedge/aortic pressure ratio (areas under the receiver operating characteristics curves 0.76 +/- 0.07, 0.78 +/- 0.08, 0.77 +/- 0.07, respectively, p = NS). Collateral flow in the recipient artery was a better predictor for ischemia than collateral flow in the donor artery or angiographic grading of collateral vessels (areas 0.90 +/- 0.05, 0.64 +/- 0.10, 0.73 +/- 0.07, respectively, p < 0.05). CONCLUSIONS: Coronary blood flow velocity analysis of the donor and recipient coronary arteries can characterize the dynamics of the collateral circulation during acute coronary occlusion. The protective effect of recruitable collateral vessels relates to an increase of flow in the donor and recipient coronary arteries due to a reduced collateral vascular resistance. This study underscores the importance of physiologic variables for the evaluation of the function of recruitable collateral vessels.

Clinical, angiographic and hemodynamic predictors of recruitable collateral flow assessed during balloon angioplasty coronary occlusion.

OBJECTIVES: We sought to determine the predictive value of factors influencing coronary collateral vascular responses in humans. BACKGROUND: There is limited information on the factors responsible for coronary collateral vascular development, despite the protective effect of collateral vessels in ischemic syndromes. METHODS: Angiography of the contralateral artery was performed during balloon coronary occlusion in 105 patients with single-vessel disease (left anterior descending coronary artery in 69 patients, left circumflex coronary artery in 4 patients, right coronary artery in 32 patients) and normal left ventricular function. Collateral vessels were graded according to the classification of Rentrop. The relative collateral vascular resistance was calculated in a subgroup of 34 patients by means of aortic pressure, coronary wedge pressure and collateral flow, defined as the transient increase of coronary blood flow velocity of the contralateral artery during balloon coronary occlusion. Ischemia during coronary occlusion was evaluated by the ST segment shift (mV) in a 12-lead electrocardiogram (ECG). RESULTS: A multivariate logistic analysis of clinical and angiographic variables revealed duration of angina (> or = 3 months, p < 0.0001), lesion severity (> or = 75% diameter stenosis, p < 0.0001) and proximal lesion location (p = 0.02) as independent factors positively associated with recruitability of collateral vessels, whereas the use of nitrates exerted an independent negative effect (p = 0.01). The regression equation yielded an overall predictive accuracy of 80%. The presence of recruitable collateral vessels during coronary occlusion resulted in a higher coronary wedge/aortic pressure ratio (mean [+/- SD] 0.35 +/- 0.13 vs. 0.27 +/- 0.12, p < 0.005), a lower relative collateral vascular resistance (6.7 +/- 7.4 vs. 21.3 +/- 10, p < 0.001) and a reduction of ECG signs of ischemia (0.14 +/- 0.19 vs. 0.38 +/- 0.33 mV, p < 0.001). The relative collateral vascular resistance was the best predictor for recruitability of collateral vessels compared with the other variables related to collateral vascular growth (p < 0.05). CONCLUSIONS: Clinical and angiographic variables predict recruitability of collateral vessels with an 80% overall accuracy. These findings are important for risk stratification of patients undergoing interventions for ischemic coronary syndromes.

Plaque inflammation in restenotic coronary lesions of patients with stable or unstable angina.

OBJECTIVES: To evaluate immunohistochemically various parameters of inflammation in coronary atherectomy specimens obtained from restenotic culprit lesions of patients presenting with either stable or unstable angina (UA). BACKGROUND: There is no information regarding the relationship between atherosclerotic plaque inflammation and the severity of the coronary syndromes in patients with restenotic coronary lesions. METHODS: A total of 37 patients with either stable angina or UA underwent directional coronary atherectomy for restenotic coronary lesions. Cryostat sections of atherectomy specimen were immunohistochemically stained with monoclonal antibodies CD68 (macrophages [MACs]), CD3 (T-lymphocytes) and alpha-actin (smooth muscle cells [SMCs]). Smooth muscle cell contents and MAC contents were planimetrically quantified as the percentage immunopositive tissue area of the total tissue area. T-lymphocytes were counted at 100-X magnification throughout the entire section and expressed as number of cells per mm2. RESULTS: Restenotic coronary lesions of patients with UA or stable angina showed no significant difference in SMC areas (31.9%+/-16.3% vs. 38.5%+/-18.8%, respectively; p = NS). However, restenotic coronary lesions of patients presenting with unstable angina contained significantly more MACs (24.4%+/-15.1% vs. 10.5%+/-5.8%, p = 0.001) and T-lymphocytes (18.8 cells/mm2+/-15.1 cells/mm2 vs. 8.6 cells/mm2+/-9.8 cells/mm2; p = 0.034) than patients with stable angina. CONCLUSIONS: These results suggested that inflammation appears to affect plaque instability in restenotic coronary lesions resulting in unstable coronary syndromes.

Quantification of collateral flow in humans: a comparison of angiographic, electrocardiographic and hemodynamic variables.

OBJECTIVES: Evaluation of collateral vascular circulation according to hemodynamic variables and its relation to myocardial ischemia. BACKGROUND: There is limited information regarding the hemodynamic quantification of recruitable collateral vessels. METHODS: Angiography of the donor coronary artery was performed before and during balloon coronary occlusion in 63 patients with one vessel disease. Patients were divided into groups of those with an absence of collateral vessels (group 1, n = 10), those with recruitable collateral vessels (group 2, n = 23) and those with spontaneously visible collateral vessels (group 3, n = 30). During balloon inflation the coronary wedge/aortic pressure ratio (Pw/Pao) was determined as were collateral blood flow velocity variables, using a 0.014" Doppler guide wire. Myocardial ischemia was defined as > or =0.1 mV ST-shift on a 12 lead electrocardiogram at 1 min coronary occlusion. RESULTS: Myocardial ischemia was present in all patients of group 1, in 14 patients of group 2 and in 3 patients of group 3. Recruitable collateral flow without ischemia showed similar hemodynamic values as in group 3 while these values were similar to group 1 in regard to the presence of recruitable collateral vessels showing ischemia. Logistic regression analysis revealed both Pw/Pao and Vi(col) as independent predictors for the function of collateral vessels. CONCLUSIONS: Hemodynamic variables of collateral vascular circulation are better markers of the functional significance of collateral vessels than is coronary angiography. The total collateral blood flow velocity integral and coronary wedge/aortic pressure ratio are good and independent predictors of the function of collateral vessels producing complementary information.

Mast cell infiltration in acute coronary syndromes: implications for plaque rupture.

OBJECTIVES: To define the role of mast cells in plaque destabilization. BACKGROUND: Inflammation is an essential feature of human coronary plaques. Macrophages and T lymphocytes are considered to contribute to destabilization of the plaques. The role of mast cells in this setting is less well studied. We therefore counted the mast cells in coronary atherectomy specimens from patients with chronic stable angina, unstable angina and severe unstable angina. METHODS: Patients studied had chronic stable angina (group 1, n=11), "stabilized" unstable angina (group 2; Braunwald's class I and II, n=11) and "refractory" unstable angina (group 3; Braunwald's class III, n=7). Samples of culprit lesions (n=29) were obtained by directional atherectomy, snap-frozen and analyzed immunohistochemically. The numbers of mast cells and T lymphocytes per square millimeter squared were counted and the areas containing macrophages and smooth muscle cells were measured by computed planimetry. RESULTS: We found that the numbers of mast cells and T lymphocytes increased from group 1 through groups 2 to 3. Specimens from group 3 also contained the largest numbers of tumor necrosis factor alpha (TNF-alpha)-positive mast cells and of matrix metalloproteinase (MMP)-9 (92 kD gelatinase)-positive macrophages. CONCLUSIONS: Unstable coronary syndromes are associated with increased numbers of mast cells in culprit lesions. Activated mast cells secrete neutral proteases capable of degrading the extracellular matrix and TNF-alpha, capable of stimulating macrophages to synthesize MMP-9. Our observations suggest that mast cells, in addition to macrophages, contribute to matrix degradation and, hence, to progression of coronary syndromes.