Relationship of diabetes, heart failure, and N-terminal pro-B-type natriuretic peptide with cardiovascular outcomes in patients with atrial fibrillation

Aims

We aim to explore the relationship of heart failure (HF) and diabetes with cardiovascular (CV) death or hospitalization for HF (HHF) and to study the clinical utility of N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) in an unselected patient population with atrial fibrillation (AF).

Methods and results

Patients with AF admitted to a tertiary academic center between January 2005 and July 2019 were identified through a search of electronic health records. We used Cox regression models adjusted for age, sex, estimated glomerular filtration rate, diabetes, HF, body mass index, prior myocardial infarction, coronary artery disease, hypertension, smoking, C‐reactive protein, and low‐density lipoprotein cholesterol. To select the most informative variables, we performed a least absolute shrinkage and selection operator Cox regression with 10‐fold cross‐validation. In total, 7412 patients (median age 70 years, 39.7% female) were included in this analysis and followed over a median of 4.5 years. Both diabetes [adjusted (Adj.) HR 1.87, 95% CI 1.55–2.25] and HF (Adj. HR 2.57, 95% CI 2.22–2.98) were significantly associated with CV death/HHF after multivariable adjustment. Compared with patients with diabetes, HF patients had a higher risk of HHF but a similar risk of CV and all‐cause death. NT‐proBNP showed good discriminatory performance (area under the curve 0.78, 95% CI 0.77–0.80) and the addition of NT‐proBNP to the covariates used for adjustment resulted in a significant area under the curve improvement (Δ = 0.04, P < 0.001). With least absolute shrinkage and selection operator, the strongest associations for CV death/HHF were obtained for NT‐proBNP [HR 1.91 per 1‐SD in log‐transformed biomarker], HF (HR 1.72), and diabetes (HR 1.56).

Conclusions

Diabetes and HF were independently associated with an increased risk of CV death/HHF in an unselected AF patient population, and NT‐proBNP improved risk assessment. These findings suggest that AF patients with diabetes and/or HF should be managed not only for their risk of stroke and systemic embolic events but also for CV death/HHF.

Validation of bedside ultrasound to predict lumbar muscle area in the computed tomography in 200 non-critically ill patients: The USVALID prospective study

BACKGROUND & AIMS

Skeletal muscle area (SMA) in the computed tomography (CT) at the third lumbar vertebra (L3) level is a proxy for whole-body muscle mass but is only performed for clinical reasons. Ultrasound is a promising tool to determine muscle mass at the bedside. It is still unclear how well ultrasound and which ultrasound measuring points can predict CT L3 SMA.

METHODS

This prospective observational trial included 200 non-critically ill patients, who underwent an abdominal CT scan for any clinical reason within 48 h before the ultrasound examination. Ultrasound muscle thickness was evaluated at 3 measuring points on the thigh and 2 measuring points on the upper arm with minimal compression. On the CT scan, the entire L3 SMA was measured based on Hounsfield units. Using a model selection algorithm based on the Bayesian information criterion (BIC) and clinical considerations, a linear prediction model for CT L3 SMA based on the ultrasound muscle thickness and other independent variables was fitted and assessed with cross-validation.

RESULTS

67,5% and 32,5% of the patients were from surgical and medical wards, respectively. Mean ultrasound muscle thickness values were between 2,2 and 3,6 cm on the thigh and between 1,4 and 2,8 cm on the upper arm. All ultrasound muscle thickness values were higher in men than in women (P < 0,05). CT L3 SMA was 40 cm² higher in men than in women (P < 0,001). The final prediction model for CT L3 SMA included the following 4 independent variables: ultrasound muscle thickness at the ventral measuring point of the thigh in the short-axis plane, sex, weight, and height. It had a similar BIC (BIC of 1515) compared to larger models with 6-8 independent variables including multiple ultrasound measuring points (BIC of 1506-1519). Additional clinical considerations to choose the final model were less time consumption when measuring a single ultrasound measuring point and better anatomical overview at the short-axis plane. The final model predicted CT L3 SMA with a R² of 0,74 (P < 0,001) and a cross-validated R² of 0,65.

CONCLUSIONS

One single ultrasound measuring point at the thigh together with sex, height and weight very well predicts CT L3 SMA across different clinical populations. Ultrasound is a safe and bedside method to measure muscle thickness longitudinally to monitor the effects of nutrition and physical therapy.

Influence of diabetes, heart failure, and NT-proBNP on cardiovascular outcomes in patients with atrial fibrillation – insights from a cohort study of 7,412 patients with extended follow-up

Background

Diabetes and heart failure (HF) promote atrial fibrillation (AF) and are associated with an increased risk of adverse cardiovascular (CV) events in patients with AF. Because of effective anticoagulation options, AF patients are now more likely to develop HF than a stroke or a systemic embolic event. Appropriate risk stratification of patients with AF should therefore not only consider the risk for stroke but also for HF events.

Methods

Patients with AF admitted to a tertiary academic center between 01/2005 and 07/2019 were identified through a search of electronic health records. The primary outcome of interest was CV death or hospitalization for HF (HHF). We used Cox regression models adjusted for age, sex, estimated glomerular filtration rate, diabetes, HF, body mass index, prior myocardial infarction, hypertension, smoking, C-reactive protein, and LDL-C. To select the most informative variables and overcome the limitations of stepwise regression procedures, we performed a least absolute shrinkage and selection operator logistic regression in a model that incorporated diabetes, HF, NT-proBNP, and the covariates for adjustment in combination with 10-fold cross-validation.

Results

In total, 7,412 patients (median age 70 years, 39.7% female) were included in the present analysis and followed over a median of 4.6 years. Both diabetes (Adjusted (Adj.) hazard ratio (HR) 1.87, 95% confidence interval (CI) 1.55 to 2.25) and HF (Adj. HR 2.57, 95% CI 2.22 to 2.98) were significantly associated with CV death/HHF after multivariable adjustment. Compared to patients with diabetes, HF patients had a higher risk of HHF but a similar risk of CV and all-cause death. There was a robust relationship between CV death/HHF and NT-proBNP (Adj. HR for 1-unit increase in standardized log-transformed biomarker 1.86, 95% CI 1.67 to 2.07). NT-proBNP showed good discriminatory performance (AUC 0.78, 95% CI 0.77–0.80), and the addition of NT-proBNP to the covariates used for adjustment resulted in a significant AUC improvement (Δ=0.04, P&lt;0.001). With least absolute shrinkage and selection operator logistic regression, the strongest associations for CV death/HHF were obtained for NT-proBNP (OR 2.69 per 1-SD in log-transformed biomarker), HF (OR 1.73), and diabetes (OR 1.65).

Conclusion

These findings suggest that the influence of diabetes and HF expand beyond the risk of stroke and systemic embolic events to CV death/HHF in an unselected AF patient population. NT-proBNP may provide improved risk assessment in AF patients.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Forest Plot

Transcatheter aortic valve replacement (TAVR) leads to an increase in the subendocardial viability ratio assessed by pulse wave analysis

Background

Pulse wave analysis (PWA) is a useful tool for non-invasive assessment of central cardiac measures as subendocardial perfusion (Subendocardial Viability Ratio, SEVR) or contractility (dP/dt_max). The immediate influence of transcatheter aortic valve replacement (TAVR) on these indices has not been investigated yet.

Methods

We prospectively enrolled 40 patients presenting with severe aortic stenosis receiving TAVR. Central pressure curves were derived from radial and carotid sites using PWA up to 2 days before and 7 days after TAVR. Parameters were compared between peripheral measurement sites. Changes in SEVR, dP/dt_max and in indices of vascular stiffness were assessed. Additionally, association of these variables with clinical outcome was evaluated during a 12-month follow-up.

Results

Central waveform parameters were comparable between measurement sites. SEVR, but not dP/dt_max, augmentation Index (AIx) or augmentation pressure height (AGPH) correlated significantly with disease severity reflected by peak transvalvular velocity and mean transvalvular pressure gradient over the aortic valve (V_max, ΔPm) [r = -0.372,p = 0.029 for V_max and r = -0.371,p = 0.021 for ΔPm]. V_max decreased from 4.5m/s (IQR:4.1–5.0) to 2.2m/s (IQR:1.9–2.7), (p<0.001). This resulted in a significant increase in SEVR [135.3%(IQR:115.5–150.8) vs. 140.3%(IQR:123.0–172.5),p = 0.039] and dP/dt_max [666mmHg(IQR:489–891) vs. 927mmHg(IQR:693–1092),p<0.001], and a reduction in AIx [154.8%(IQR:138.3–171.0) vs. 133.5%(IQR:128.3–151.8),p<0.001] and AGPH [34.1%(IQR:26.8–39.0) vs. 25.0%(IQR 21.8–33.7),p = 0.002], confirming the beneficial effects of replacing the stenotic valve. No association of these parameters could be revealed with outcome.

Conclusions

PWA is suitable for assessing coronary microcirculation and contractility mirrored by SEVR and _maxdP/dt in the setting of aortic stenosis. PWA parameters attributed to vascular properties should be interpreted with caution.

2MHz ultrasound enhances t-PA-mediated thrombolysis: comparison of continuous versus pulsed ultrasound and standing versus travelling acoustic waves

In addition to fibrinolytic enzymes, ultrasound has the potential to enhance thrombolysis. High frequency ultrasound has the advantage that a combination of diagnostic and therapeutic ultrasound with only one device is possible. Therefore, we investigated the optimal high frequency (2 MHz) ultrasound field characteristics and application mode in vitro. Continuous ultrasound significantly enhanced rt-PA mediated thrombolysis: in a travelling wave field thrombolysis was augmented by 49.0 ± 14.7% and in a standing wave field by 34.8 ± 7.3%. In an intermittent application mode (1Hz, 10Hz, 100Hz, 1kHz) most efficient results were obtained for both wave fields using 1 Hz (46.4 ± 10.7% and 39.1 ± 6.6%, respectively). Referring to a possible in vivo application our in vitro data suggests that an intermittent application of a 2 MHz high frequency ultrasound using a travelling wave field would be the most potent application for lysing blood clots.

Predictive Value of PAI-1 Plasma Activity and Thallium Perfusion Imaging for Restenosis after Percutaneous Transluminal Angioplasty in Clinically Asymptomatic Patients

Background. The main long-term complication of percutaneous transluminal coronary angioplasty (PTCA) is restenosis that occurs in 30-50 percent of all primary successful cases. The purpose of this study was to evaluate the predictive value of changes in plasminogen activator inhibitor-1 (PAI-1) activity and of thallium dipyridamole perfusion imaging performed 3 months after successful angioplasty. All patients were asymptomatic at evaluation. The results of these two noninvasive tests were compared with the angiographic outcome after 6 months.

Methods and Patients. Twenty-five patients were included in this prospective study. All patients had single vessel disease, successful angioplasty and were free of clinical symptoms 3 months after angioplasty that would suggest late restenosis. In 12/25 patients (48%) angiographic restenosis (percent diameter stenosis >50%) was determined by follow-up angiography 6 months after angioplasty. PAI-1 plasma activity was determined by a functional titration assay and increase or decrease of PAI-1 plasma activity was evaluated between values obtained before and 3 months after angioplasty. In 7/25 (28%) patients PAI-1 plasma activity increased to more than 90% of pre-angioplasty values. This increase correlated with angiographic restenosis evaluated 6 months after angioplasty (sensitivity 42%, specificity 85%, positive predictive value 71%, and negative predictive value 61%). Tl-201-perfusion imaging was performed 3 months after angioplasty. This test was indicative for subsequent restenosis in 5/25 patients (sensitivity 33%, specificity 100%, positive predictive value 62%, and negative predictive value 100%). In 10/25 (40%) patients at least one of the two non-invasive tests performed 3 months after angioplasty predicted angiographic restenosis at 6 months; the combined use of PAI-1 and Tl-201-perfusion imaging resulted in increased sensitivity (67%) and high specificity (85%).

Conclusion. The results of this study indicate that an increase of PAI-1 plasma activity may improve the predictive value for restenosis of Tl-201-scintigraphy performed 3 months after angioplasty even in asymptomatic patients.

Music-induced prolongation of heart rate corrected QT intervals from electrocardiogram recordings of healthy preterm pregnant women

AIM

Women do have longer QTc intervals compared to men. The aim of this study was to investigate as-yet undocumented effects of music on QTc intervals from electrocardiogram (ECG) recordings compared to various cardiovascular parameters of women in the prenatal phase.

METHODS

Forty-four healthy women in pregnancy were exposed to quiet surroundings (Q), self-selected slow music (S), and investigator-provided fast music (F) with different rhythm and frequency characteristics for 3 min each during their routine cardiotocography investigation. QTc intervals from ECG recordings were calculated according to the formulas of Bazett, Fridericia, and Sagie.

RESULTS

QTc durations (Bazett) increased from 0.396±0.02 (Q) to 0.401±0.02 s (S) and to 0.407±0.03 s (F). The increase in QTc (delta QTc) value for slow (S) and fast (F) music was found to be 5.3 (S) and 10.1 ms (F, milliseconds) when compared to quiescent (Q) conditions showing a highly significant tripled P-value of 0.002 (Q vs. F). Similar results were found using alternate frequency corrections (Fridericia, Sagie) - QTc (delta QTc): 8.1 (Fridericia) and 7.2 ms (Sagie), quiescent vs. F, with P<0.001. None of the tests for other cardiovascular parameters showed significant differences.

CONCLUSIONS

As shown from our data, music with different rhythm and frequency characteristics may prolong QTc intervals in healthy preterm pregnant women and may add to other risk factors (e.g., preexisting QTc prolongation or application of QTc prolonging drugs). These data could prove to be relevant in the primary prevention recommendations for women at risk for arrhythmic patterns during pregnancy.

Bioimpedance cardiography in pregnancy: A longitudinal cohort study on hemodynamic pattern and outcome

Background

Pregnancy associated cardiovascular pathologies have a significant impact on outcome for mother and child. Bioimpedance cardiography may provide additional outcome-relevant information early in pregnancy and may also be used as a predictive instrument for pregnancy-associated diseases.

Methods

We performed a prospective longitudinal cohort trial in an outpatient setting and included 242 pregnant women. Cardiac output and concomitant hemodynamic data were recorded from 11^th–13^th week of gestation every 5^th week as well as at two occasions post partum employing bioimpedance cardiography.

Results

Cardiac output increased during pregnancy and peaked early in the third trimester. A higher heart rate and a decreased systemic vascular resistance were accountable for the observed changes. Women who had a pregnancy-associated disease during a previous pregnancy or developed hypertension or preeclampsia had a significantly increased cardiac output early in pregnancy. Furthermore, an effect of cardiac output on birthweight was found in healthy pregnancies and could be confirmed with multiple linear regression analysis.

Conclusions

Cardiovascular adaptation during pregnancy is characterized by distinct pattern described herein. These may be altered in women at risk for preeclampsia or reduced birthweigth. The assessment of cardiac parameters by bioimpedance cardiography could be performed at low costs without additional risks.

Transtemporal ultrasound application potentially elevates brain temperature: results of an anthropomorphic skull model

PURPOSE

Transtemporal sonothrombolysis is a tool for a more effective treatment in acute stroke patients. However, some reports revealed side effects, which might be potentially connected to temperature elevation. To gain better insight into cerebral temperature changes during transtemporal sonication, diagnostic and therapeutic ultrasound (US) applications were evaluated using an anthropomorphic skull model.

MATERIALS AND METHODS

The impact of diagnostic (PW-Doppler, 1.8-MHz, 0.11 W/cm², TIC 1.2) and therapeutic (1-MHz and 3-MHz, 0.07 - 0.71 W/cm², continuous and pulsed mode) US application on temperature changes was evaluated at the level of muscle/temporal bone (TB), TB/brain, brain and at the middle cerebral artery (MCA) using 4 miniature thermocouples along the US beam. Sonication lasted 120 minutes.

RESULTS

Diagnostic ultrasound revealed a maximum temperature increase of 1.45°/0.60°/0.39°/0.41°C (muscle/TB, TB/brain, brain, MCA) after 120 minutes. Therapeutic-1-MHz ultrasound raised temperature by 4.33°/2.02°/1.05 °C/0.81°C (pulsed 1:20) and by 10.38°/4.95°/2.43°/2.08°C (pulsed 1:5) over 120 minutes. Therapeutic-3-MHz US raised temperature by 4.89°/2.56°/1.24/1.25°C (pulsed 1:20) and by 14.77°/6.59°/3.56°/2.86°C (pulsed 1:5) over 120 minutes, respectively. Continuous application of therapeutic US (1-MHz and 3-MHz) led to a temperature increase of 13.86°/3.63°/1.66°/1.48°C and 17.09°/4.28°/1.38/0.99°C within 3 minutes.

CONCLUSION

Diagnostic PW-Doppler showed only a moderate temperature increase and can be considered as safe. Therapeutic sonication is very powerful in delivering energy so that even pulsed application modes resulted in significant and potentially harmful temperature increases.

Thermal effects of diagnostic ultrasound in an anthropomorphic skull model

PURPOSE

Exposure to diagnostic ultrasound (US) can significantly heat biological tissue although conventional routine examinations are regarded as safe. The risk of unwanted thermal effects increases with a high absorption coefficient and extended insonation time. Certain applications of transcranial diagnostic US (TC-US) require prolonged exposure. An anthropomorphic skull model (ASM) was developed to evaluate thermal effects induced by TC-US of different modalities. The objective was to determine whether prolonged continuous TC-US application results in potentially harmful temperature increases.

MATERIALS AND METHODS

The ASM consists of a human skull with tissue mimicking material and exhibits acoustic and anatomical characteristics of the human skull and brain. Experiments are performed with a diagnostic US device testing four different US modalities: Duplex PW (pulsed wave) Doppler, PW Doppler, color flow Doppler and B-mode. Temperature changes are recorded during 180 minutes of insonation.

RESULTS

All measurements revealed significant temperature increases during insonation independent of the US modality. The maximum temperature elevation of + 5.25° C (p < 0.001) was observed on the surface of the skull exposed to duplex PW Doppler. At the bone-brain border a maximum temperature increae of + 2.01 °C (p < 0.001) was noted. Temperature increases within the brain were < 1.23 °C (p = 0.001). The highest values were registered using the duplex PW Doppler modality.

CONCLUSION

TC-US induces significant local heating effects in an ASM. An application duration that extends routine clinical periods causes potentially harmful heating especially in tissue close to bone. TC-US elevates the temperature in the brain mimicking tissue but is not capable of producing harmful temperature increases during routine examinations. However, the risk of thermal injury in brain tissue increases significantly after an exposure time of > 2 hours.

Dabigatran in patients with atrial fibrillation: perioperative and periinterventional management

In any type of invasive surgery, the patient’s individual risk of thromboembolism has to be weighed against the risk of bleeding. Based on various everyday situations in clinical routine, the purpose of the present expert recommendations is to provide appropriate perioperative and periinterventional management for patients with atrial fibrillation undergoing long-term treatment with the thrombin inhibitor dabigatran. As we currently have no routine laboratory test to measure therapeutic levels of the substance or the risk of bleeding, general measures such as a standardized documentation of the patient’s history, a sufficient time interval between the last preoperative dose and the procedure, and careful control of local hemostasis should be given special attention.

An iatrogenic coronary arteriovenous fistula causing a steal phenomenon: an intracoronary Doppler study

We present the case of a 67-year-old man in whom a guidewire broke at rotablation of the right coronary artery, creating an iatrogenic aneurysmal arteriovenous fistula to the coronary sinus. Successful Doppler wire-guided fistula occlusion by percutaneous coil embolization lead to normalization of coronary blood flow and relief of the patient's symptoms. Myocardial ischemia in this patient may have been due to a steal phenomenon caused by coronary artery fistulae, as suggested by blood flow velocity data obtained before and after fistula occlusion.

Randomized blinded clinical trial of intracoronary brachytherapy with 90Sr/Y beta-radiation for the prevention of restenosis after stent implantation in native coronary arteries in diabetic patients

BACKGROUND

We report a double-blind, randomized clinical trial of intracoronary beta-radiation for prevention of restenosis after stent implantation in native coronary de novo lesions in diabetic patients.

METHODS

After successful stent implantation in native coronary de novo lesions, 106 lesions in 89 diabetic patients were randomly allocated to treatment with beta-radiation with 18 Gy at 1 mm vessel depth (n = 53) or placebo treatment (n = 53).

RESULTS

Angiographic analysis at 9 month follow-up revealed a late lumen loss of 0.7+/-0.9 mm in the radiotherapy group versus 1.2+/-0.8 mm in the control group at the injured segment (P = 0.006), 0.9+/-1.0 versus 1.3+/-0.7 mm at the radiated segment (P = 0.02), and 0.9+/-1.0 versus 1.3+/-0.7 mm at the target segment (P = 0.04) (defined as active source length plus 5mm on proximal and distal sites). Binary restenosis rates were significantly lower in the radiation group in all subsegments (injured segment: 10.9 versus 37.3%, P = 0.003; radiated segment: 21.7 versus 49.0%, P = 0.005; target segment: 23.9 versus 49.0%, P = 0.01). Target lesion revascularization for restenosis was required in nine lesions (17.6%) in the radiotherapy group versus 18 (34.0%) in the placebo group (P = 0.05). Late thrombosis occurred in four radiated patients (after premature discontinuation of antiplatelet therapy in all), resulting in a major adverse clinical event rate of 37.2% in the brachytherapy group versus 38.6% in the placebo group (P = ns).

CONCLUSIONS

In diabetic patients with de novo coronary lesions, intracoronary radiation after stent implantation significantly reduced restenosis. However, this clinical benefit was reduced by the frequent occurrence of late thrombosis.

Ultrasound thrombolysis

Cardiovascular diseases are a major cause of mortality in the developed world. Efficacy of thrombolysis plays an important role in the management of acute myocardial infarction and cerebral insult both in the acute event and in the long-term outcome of these patients. New adjunctive strategies have been tested, therefore, to make thrombolytic therapies more effective and safer. Ultrasound Thrombolysis is a technique which showed promising results under in vitro conditions and in animal studies. Now clinical trials have to prove if it is also feasible for clinical application. This report gives an overview on different technical approaches and their current performances in the clinical setting. All original articles are chronologically ordered in tables providing detailed information on each study concerning experimental design, acoustical parameters and thrombolysis outcome.

Ultrasound affects distribution of plasminogen and tissue-type plasminogen activator in whole blood clots in vitro

Ultrasound of 2 MHz frequency and 1.2 W/cm(2) acoustic intensity was applied to examine the effect of sonication on recombinant tissue-type plasminogen activator (rt-PA)-induced thrombolysis as well as on the distribution of plasminogen and t-PA within whole blood clots in vitro. Thrombolysis was evaluated quantitatively by measuring clot weight reduction and the level of fibrin degradation product D-dimer (FDP-DD) in the supernatant. Weight reduction in the group of clots treated both with ultrasound and rt-PA was 35.2% +/-6.9% which is significantly higher (p<0.0001) than in the group of clots treated with rt-PA only (19.9% +/-4.3%). FDP-DD level in the supernatants of the group treated with ultrasound and rt-PA increased sevenfold compared to the group treated with rt-PA alone, (14895 +/-2513 ng/ml vs. 2364 +/-725 ng/ml). Localization of fibrinolytic components within the clots was accomplished by using gel-entrapping technique and immunohistochemistry. Spatial distributions of t-PA and plasminogen showed clearly that ultrasound promoted the penetration of rt-PA into thrombi significantly (p<0.0001), and broadened the zone of lysis from 8.9 +/-2.6 microm to 21.2 +/-7.2 microm. We speculate that ultrasound enhances thrombolysis by affecting the distribution of rt-PA within the clot.

Predictive value of plasma plasminogen activator inhibitor-1 for coronary restenosis: dependence on stent implantation and antithrombotic medication

BACKGROUND

The plasmin activation system is involved in the development of restenosis after percutaneous coronary interventions (PCI). Conflicting data exist concerning the role of plasminogen activator inhibitor-1 (PAI-1) and its predictive value for restenosis.

OBJECTIVES

To evaluate the fibrinolytic response to injury after PCI with or without stent implantation on different antithrombotic medications and its relation to late restenosis.

PATIENTS AND METHODS

Eighty consecutive patients with successful PCI without (balloon only; n = 37) or with stent implantation (stent; n = 43) on different antithrombotic regimes (balloon only, aspirin; stent, aspirin/coumadin/dipyridamole vs. aspirin/ticlopidine). Blood samples were taken at baseline and up to 7 days after PCI and PAI-1 active antigen and tissue plasminogen activator (t-PA) antigen were determined. Restenosis was angiographically determined after 6 months.

RESULTS

PCI increased both t-PA and PAI-1 levels (P < 0.001), with a significant prolonged and pronounced increase in stent vs. balloon-only patients (P < 0.05). Restenosis (stent 26%; balloon 38%) was significantly correlated to an attenuated PAI-1 increase after 24 h in the ticlopidine group (P = 0.007; restenosis, relative Delta PAI-1 + 50 +/- 28%; non-restenosis, + 139 +/- 50%), but not in the coumadin group. In the balloon-only group late restenosis (ISR) was associated with a trend for an augmented PAI-1 increase after 24 h.

CONCLUSIONS

Coronary stent implantation significantly increases t-PA and PAI-1 plasma levels up to 1 week compared with balloon angioplasty alone. ISR in ticlopidine-treated patients was associated with an attenuated early PAI-1 active antigen increase. A less than 50% increase 24 h after stent implantation under ticlopidine treatment may identify patients at risk for the development of ISR.

Can a Commercial Diagnostic Ultrasound Device Accelerate Thrombolysis?

Background and Purpose— Recently, 3 clinical trials revealed encouraging results in recanalization and clinical outcome in acute stroke patients when 2-MHz transcranial Doppler monitoring was applied. This study investigated whether a 1.8-MHz commercial diagnostic ultrasound device has the potential to facilitate thrombolysis using an in vitro stroke model.

Methods— Duplex-Doppler, continuous wave-Doppler, and pulsed wave (PW)-Doppler were compared on their impact on recombinant tissue plasminogen activator (rtPA)–mediated thrombolysis. Blood clots were transtemporally sonicated in a human stroke model. Furthermore, ultrasound attenuation of 5 temporal bones of different thickness was determined.

Results— In comparison, only PW-Doppler accelerated rtPA–mediated thrombolysis significantly. Without temporal bone, PW-Doppler plus rtPA showed a significant enhancement in relative clot weight loss of 23.7% when compared with clots treated with rtPA only (33.9±5.5% versus 27.4±5.2%; P <0.0005). Ultrasound attenuation measurements revealed decreases of the output intensity of 86.8% (8.8 dB) up to 99.2% (21.2 dB), depending on temporal bone thickness (1.91 to 5.01 mm).

Conclusion— Without temporal bone, PW-Doppler significantly enhanced thrombolysis. However, because of a high attenuation of ultrasound by temporal bone, no thrombolytic effect was observed in our in vitro model, although Doppler imaging through the same temporal bone was still possible.

Adventitial response to intravascular brachytherapy in a rabbit model of restenosis

BACKGROUND

The incidence of late major adverse cardiac events (MACE) after coronary brachytherapy is higher than in controls. Because expansive remodeling has been shown to correlate with poor clinical outcome after vascular interventions, we studied adventitial changes after intravascular irradiation in a rabbit model.

METHODS

Twenty normolipidemic rabbits underwent balloon injury in both external iliac arteries. One artery was assigned for subsequent irradiation with a 90Y source (15 Gy or 30 Gy at 0.5 mm in the vessel wall). After four weeks morphometric measurements were made and cell density and collagen amount determined. Staining for Ki67 identified proliferating cells; apoptotic cells were identified by TUNEL staining. Proliferative and apoptotic indices were calculated as the number of respective positive cells/total cell count x100.

RESULTS

The neointimal area decreased to 0.27 +/- 0.3 mm2 after irradiation compared with 0.55 +/- 0.2 mm2 in controls (p=0.007), whereas adventitial area increased from 0.62 +/- 0.3 mm2 to 0.87 +/- 0.3 mm2 (p=0.02). Irradiation reduced both the proliferative (0.95 +/- 2.6 vs. 3.73 +/- 4.7, p=0.026) and apoptotic (0.006 +/- 0.02 vs. 0.107 +/- 0.2, p=0.03) indices in the neointima, but not in the other arterial-wall layers. Collagen amount and arterial remodeling did not differ between the groups. There was no difference between 15 and 30 Gy in any of the parameters, although adventitial thickening was more pronounced in the high-dose group.

CONCLUSIONS

In normolipidemic rabbits, intravascular beta-irradiation after balloon angioplasty is associated with an increase in neoadventitia and a reduction of neointima. It is conceivable that this phenomenon may contribute to the increased incidence of late MACE after vascular brachytherapy.

Inhibition of interleukin-1beta convertase is associated with decrease of neointimal hyperplasia after coronary artery stenting in pigs

Inhibition of IL-1beta convertase has been shown to decrease inflammation and apoptosis, which are features of the neointimal development after vascular interventions. The aim of our study was to reduce neointimal proliferation after stenting of the porcine coronary artery, using the irreversible IL-1beta convertase and caspase-1 inhibitor acetyl-tyrosinyl-valyl-alanyl-aspartyl-chloromethyl-ketone (Ac-YVAD-cmk). Before coronary stent implantation, 8 pigs received an intracoronary infusion of 50 mg Ac-YVAD-cmk into the left coronary artery (group 1, n = 8), while 8 animals served as untreated controls (group 2). After 4 weeks, coronary angiography and intracoronary ultrasound (IVUS) with 3D measurements were performed. IVUS revealed a smaller in-stent intimal volume (27.3 +/- 11.6 vs. 75.8 +/- 18.4 mm3, p < 0.005) and a decreased maximal percentage area stenosis (36.1 +/- 8.5 vs. 69.0 +/- 8.2%, p < 0.001) in group 1 vs. group 2. A smaller maximal neointimal thickness (0.63 +/- 0.28 vs. 1.75 +/- 0.94 mm, p < 0.005) and a decreased maximal neointimal area (2.14 +/- 1.29 vs. 5.03 +/- 1.92 mm2, p < 0.005), assessed by computerized planimetry, were found in group 1 vs. group 2. Lower apoptotic indices of the neointimal cells were observed in the treated animals (3.0 vs. 13.4% of total intimal cells, p < 0.05). The coronary arterial tissue IL-1beta level was significantly decreased in the animals treated with Ac-YVAD-cmk (0.254 +/- 0.162 vs. 0.463 +/- 0.307 pg/mg protein, p < 0.05), and exhibited a positive linear correlation (r = 0.581, p = 0.013) with the in-stent plaque volume. In conclusion, intracoronary administration of Ac-YVAD-cmk before coronary artery stenting results in significantly decreased neointimal hyperplasia due to the inhibition of local IL-1beta production and decreased neointimal apoptosis.

Arterial compliance: a diagnostic marker for atherosclerotic plaque burden?

BACKGROUND

Previous studies have shown atherogenesis to be related with increased vessel stiffness. Measures of the arterial compliance can be performed noninvasively from pressure pulse contour analysis of arterial waveforms. In this prospective study we aimed to analyze to what extent vessel compliance can reflect the angiographic coronary artery status.

METHODS

Large and small arterial elasticity indices (LAEI in milliliters per mm Hg x 10 and SAEI in milliliters per mm Hg x 100) were measured in 151 patients on the radial artery with the PulseWave Sensor HDI device. All patients were classified into diffuse-coronary artery disease (CAD) (defined as stenosis length >15 mm), focal-CAD (defined as stenosis length between 1 and 15 mm), or no-CAD.

RESULTS

We found both LAEI and SAEI to be reduced in the diabetic group (LAEI: 11.2 +/- 2.9 v 13.4 +/- 4.5, P =.006; SAEI: 3.7 +/- 1.6 v 4.7 +/- 2.4, P =.01). Inverse association was seen between age and LAEI (r = -0.41; P <.001) and SAEI (r = -0.38; P <.001). No-CAD was found in 31 patients, focal-CAD in 64 patients, and diffuse-CAD in 56 patients. Mean LAEI were 13.8 +/- 3.5, 13.7 +/- 4.7, and 11.3 +/- 3.5 in the groups no-CAD, focal-CAD, and diffuse-CAD, respectively (P =.004), (no-CAD versus diffuse-CAD: P =.04; focal-CAD versus diffuse-CAD: P =.009). Respective SAEI values were 5.6 +/- 2.5, 5.0 +/- 2.1, and 3.1 +/- 1.6 (P <.001), (no-CAD versus diffuse-CAD: P <.001; focal-CAD versus diffuse-CAD: P <.001). Multivariate analysis revealed SAEI (P <.001), hypercholesterolemia (P =.005), systolic blood pressure (BP) (P <.001), mean arterial BP (P <.001), pulse pressure (P =.003), and male gender (P =.001) to be diagnostic markers of the type of vessel disease.

CONCLUSIONS

Compliance measurements may be used for identification of patients with diffuse atherosclerotic processes of the coronary arteries.

Percutaneous interventions in radiation-associated coronary in-stent restenosis

This study was performed to evaluate the outcome of percutaneous revascularization in "edge restenoses" developing after radioactive stent implantation in de novo and in-stent lesions. Twenty-one consecutive patients undergoing target lesion revascularization (TLR) at any follow-up after phosphorus-32 radioactive stent implantation were included in this study. We assessed the incidence of death, myocardial infarction, repeated TLR and recurrent angina over the following 18 months. After 6 months, TLR rate was 28.6%, and no stent thromboses, deaths or Q-wave myocardial infarctions occurred. Among the patients with TLR there were significantly more subjects who had received a radioactive stent in a previous in-stent restenosis (66.7% vs. 0% in patients without second restenosis; P <0.001), or who had received two radioactive stents (83.3% vs. 33.3%; P = 0.038). After 18 months, TLR rate was 33.3%, and two patients (9.5%) had died. Restenosis after intravascular radiotherapy can be safely treated by percutaneous interventional techniques, yielding an acceptable clinical result within 18 months.

2MHz ultrasound enhances t-PA-mediated thrombolysis: comparison of continuous versus pulsed ultrasound and standing versus travelling acoustic waves

In addition to fibrinolytic enzymes, ultrasound has the potential to enhance thrombolysis. High frequency ultrasound has the advantage that a combination of diagnostic and therapeutic ultrasound with only one device is possible. Therefore, we investigated the optimal high frequency (2 MHz) ultrasound field characteristics and application mode in vitro. Continuous ultrasound significantly enhanced rt-PA mediated thrombolysis: in a travelling wave field thrombolysis was augmented by 49.0 +/- 14.7% and in a standing wave field by 34.8 +/- 7.3%. In an intermittent application mode (1Hz, 10Hz, 100Hz, 1kHz) most efficient results were obtained for both wave fields using 1 Hz (46.4 +/- 10.7% and 39.1 +/- 6.6%, respectively). Referring to a possible in vivo application our in vitro data suggests that an intermittent application of a 2 MHz high frequency ultrasound using a travelling wave field would be the most potent application for lysing blood clots.

[Manual compression versus mechanical compression device (FemoStop) after diagnostic coronary angiography with/without intervention]

BACKGROUND

The aim of our study was to evaluate the practicability and the complication rates of two different forms of the post-angiographic closure of the femoral artery.

METHODS

We randomized 239 patients over a time period of 4 months to either a mechanical compression system (FemoStop, 111 patients) or to conventional manual compression (128 patients). A Doppler-sonographic examination was performed if the patient reported pain of the puncture site, or if auscultation or palpation suspected a complication on the day after compression.

RESULTS

After manual compression, Doppler-sonography had to be performed in 21 patients (16.4%). In the FemoStop-group only 14 patients (12.6%, p = ns) had to be referred for ultrasound examination. A complication was detected in 13 patients (10.1%) after manual compression and in 5 patients (4.5%, p = ns) after closure with the mechanical device. The incidence of a pseudo-aneurysma or of an arterio-venous fistula did not show any difference between the two groups. In 6 patients of the manual compression group a hematoma was found (p < 0.05), whereas no hematoma occurred in the FemoStop-group. None of the hematomas required the infusion of blood concentrates or surgical correction. In one patient with extreme overweight the mechanical compression device could not be applied. The mechanical compression device was used successfully in patients who had received heparin, acetyl-salicyl-acid or a glycoprotein IIb/IIIa receptor antagonist and in whom a significantly longer compression time and higher complication rate could have been expected. In addition, post-angiographic closure with the was less time consuming for the staff involved. In contrast, the higher cost of the mechanical compression device presents a disadvantage.

CONCLUSION

A mechanical compression device (FemoStop) can be used successfully in routine post-angiographic management and shows a trend to lower complication rates than manual compression and increased acceptance by patients and physicians. However, the overall costs are higher for the mechanical compression device.

In vitro thrombolysis enhanced by standing and travelling ultrasound wave fields

Success of thrombolytic therapy depends on penetration of recombinant tissue plasminogen activator (rt-PA) into clots. Ultrasound (US) of therapeutic quality accelerates thrombolysis in vitro. As yet, only the effects of travelling acoustic waves on thrombolysis have been investigated, and the impact of standing acoustic waves has been neglected. In the present study, we examined the effects of standing and travelling US wave fields applied continuously for 1 h (frequency 2 MHz, acoustic intensity 1.2 W/cm(2)) on thrombolysis enhancement by measuring clot weight reduction and concentration of fibrin degradation product D-dimer (FDP-DD) produced from clots subjected to rt-PA. The level of FDP-DD was 1.8 times greater in travelling than in standing acoustic waves. Thrombolysis enhancement was 46.0 +/- 20.8% in standing and 116.8 +/- 23.1% in travelling acoustic waves. Travelling waves enhanced thrombolysis significantly more (p < 0.0001) than did standing waves.

Vascular morphometric changes after radioactive stent implantation: a dose-response analysis

OBJECTIVES

The goal of this study was to evaluate the dose-dependency of morphometric changes in the coronary arterial wall after radioactive stenting.

BACKGROUND

Radioactive stents have been found to reduce intrastent intimal hyperplasia (IIH) but lead to a characteristic type of restenosis occurring predominantly at the stent edges.

METHODS

Fifteen patients underwent intravascular ultrasound (IVUS) examination after implantation of a P-32 radioactive stent and at the six-month follow-up. The post-stent IVUS measurements on seven predefined locations of each lesion were subjected to a computer algorithm for the development of dose-volume histograms (DVH). Thus, we derived the radiation doses delivered to at least 10% and 90% of the adventitia (DV10, DV90). The IIH and vascular remodeling at follow-up were correlated with the doses in each segment.

RESULTS

The IIH was most pronounced at the stent edges and lowest in the stent-body, whereas we detected a significant expansive remodeling within the stent body. The delivered doses correlated with a decreased IIH (r = 0.52, p < 0.001 for DV10 and r = 0.62, p < 0.001 for DV90) and with expansive remodeling (r = 0.48, p = 0.009 for DV10 and r = 0.50, p = 0.006 for DV90). A DV10 >90 Gy or a DV90 >15 Gy reduced IIH and induced expansive remodeling. Plaque growth was not reduced by radioactive stents.

CONCLUSIONS

The DVH analysis reveals a dose-dependent increase of external elastic lamina area behind radioactive stents, whereas plaque growth is not reduced but inverted into an outward direction from the stent. A DV10 >90 Gy or a DV90 >15 Gy results in a beneficial long-term outcome after radioactive stenting.

[Chlamydia antibody titers in patients with coronary disease: relations to age and clinical stage]

BACKGROUND AND AIM

Atherosclerosis and its clinical sequelae are responsible for the highest death rate in industrialized countries. Seroepidemiological, pathological and immunohistochemical studies have suggested a relation between Chlamydia pneumoniae infection and the development of coronary sclerosis. Aim of this study was to investigate the frequency distribution of Chlamydia pneumoniae antibody titers in patients with different clinical stages of coronary artery disease (CAD) and patients without CAD as well as a possible age dependence of antibody titers within the study groups. For this purpose, 522 consecutive patients of a cardiology ward were investigated, over a period of 10 months, for the presence of Chlamydia pneumoniae antibodies (IgG, IgA, IgM) using specific ELISA's. In general, there was no difference in the frequency of positive Chlamydia antibody titers between CAD patients and the control group. Only in the subgroup of unstable CAD-patients < 50 years a tendency of increased antibody titers was present. Patients with stable angina, unstable angina, or acute myocardial infarction exhibited no significant differences in the rate of infection between the different age groups (p < 0.117). In contrast, there was a significant increase in positive Chlamydia pneumoniae antibodies with increasing age in the control group (p = 0.002). The relatively high incidence of positive Chlamydia pneumoniae antibody titers in young CAD patients, which is associated with a loss of age-dependent increase of the antibody titers in the CAD group, might indicate a specific role of Chlamydia pneumoniae infections for the manifestation of premature CAD (before the age of 50). Due to the increased rate of Chlamydia pneumoniae infections with increasing age, the determination of Chlamydia pneumoniae antibody titers does not allow reliable conclusions on the infectious pathogenesis of CAD. Furthermore, our unability to demonstrate differences in antibody titers between CAD patients with stable angina, unstable angina, and acute myocardial infarction suggests that acute Chlamydia pneumoniae infections are not responsible for the development of acute coronary syndromes.

PAI-I 4G/5G polymorphism and sudden cardiac death in patients with coronary artery disease

The 4G/5G polymorphism of the plasminogen activator inhibitor type I (PAI-I) gene is involved in coronary artery disease (CAD), with the highest risk in 4G/4G homozygotes. The role of PAI-I polymorphism in patients suffering from CAD and history of sudden cardiac death (SCD) has not been addressed yet. We studied the frequency distribution of the PAI-I gene to test the hypothesis that the 4G/4G genotype favors myocardial ischemia and, even in the absence of acute infarction, promotes SCD in patients with CAD.

METHODS

The PAI-I 4G/5G genotypes and PAI-I antigen plasma levels were determined in 97 patients with CAD and a history of SCD treated with an implantable cardioverter defibrillator (ICD) (defibrillator group) comparing to 113 patients with CAD but no history of SCD (control group).

RESULTS

The defibrillator group consisted of significantly more 4G/4G homozygotes and higher PAI-I levels than the control group (44% vs. 24%, 173+/-41 vs. 144+/-49 ng/ml; P<.01). The carriers of 4G allele had a significantly higher risk for SCD (odds ratio (OR) 1.9) with the highest risk in the 4G/4G genotype (OR 3.6, P<.01).

CONCLUSION

These results suggest that the PAI-I 4G/4G genotype is associated with SCD in patients suffering from CAD.

Fatal late coronary thrombosis after implantation of a radioactive stent: postmortem angiographic and histologic findings--case report

Postmortem angiography and histologic analysis of a fatal coronary thrombosis 4 months after implantation of a radioactive stent are described. Histologic findings suggested incomplete re-endothelialization in the segment with the stent. Ionizing radiation may delay re-endothelialization after revascularization, thus maintaining the thrombogenicity of the irradiated vessel segment. Thus, prolonged antiplatelet therapy should be considered after intravascular radiation therapy.

Dose–volume histograms based on serial intravascular ultrasound: a calculation model for radioactive stents

BACKGROUND AND PURPOSE

Radioactive stents are under investigation for reduction of coronary restenosis. However, the actual dose delivered to specific parts of the coronary artery wall based on the individual vessel anatomy has not been determined so far. Dose-volume histograms (DVHs) permit an estimation of the actual dose absorbed by the target volume. We present a method to calculate DVHs based on intravascular ultrasound (IVUS) measurements to determine the dose distribution within the vessel wall.

MATERIALS AND METHODS

Ten patients were studied by intravascular ultrasound after radioactive stenting (BX Stent, P-32, 15-mm length) to obtain tomographic cross-sections of the treated segments. We developed a computer algorithm using the actual dose distribution of the stent to calculate differential and cumulative DVHs. The minimal target dose, the mean target dose, the minimal doses delivered to 10 and 90% of the adventitia (DV10, DV90), and the percentage of volume receiving a reference dose at 0.5 mm from the stent surface cumulated over 28 days were derived from the DVH plots. Results were expressed as mean+/-SD.

RESULTS

The mean activity of the stents was 438+/-140 kBq at implantation. The mean reference dose was 111+/-35 Gy, whereas the calculated mean target dose within the adventitia along the stent was 68+/-20 Gy. On average, DV90 and DV10 were 33+/-9 Gy and 117+/-41 Gy, respectively. Expanding the target volume to include 2.5-mm-long segments at the proximal and distal ends of the stent, the calculated mean target dose decreased to 55+/-17 Gy, and DV 90 and DV 10 were 6.4+/-2.4 Gy and 107+/-36 Gy, respectively.

CONCLUSIONS

The assessment of DVHs seems in principle to be a valuable tool for both prospective and retrospective analysis of dose-distribution of radioactive stents. It may provide the basis to adapt treatment planning in coronary brachytherapy to the common standards of radiotherapy.

Plasma levels of C-reactive protein after coronary stent implantation

AIMS

This study was designed to investigate the role of inflammation on the occurrence of angiographic restenosis 6 months after coronary stent implantation and the influence of different kinds of antithrombotic and antiplatelet strategies on inflammation.

METHODS AND RESULTS

In an open randomized trial, 40 consecutive patients were treated with aspirin (100 mg. day(-1)) and either ticlopidine (2x250 mg. day(-1)) (n=17), or phenprocoumon (INR 2.0-3.0) and dipyridamole (3x160 mg. day(-1)) (n=23) after successful elective coronary stent implantation. Plasma levels of C-reactive protein were determined one day before stent implantation and serially thereafter twice daily up to 120 h. C-reactive protein plasma levels increased significantly (P<0.0001) after stent implantation. Phenprocoumon and dipyridamole or ticlopidine had no effect on C-reactive protein plasma levels (P=0.51) or the occurrence of angiographic restenosis (P=0.48). C-reactive protein plasma levels were significantly higher in patients with lesion type C compared to types A or B (P=0.035), respectively. C-reactive protein plasma levels were significantly higher and mean shoulder levels occurred 48 h later in patients with restenosis compared to patients without restenosis after 6 months (P=0.038).

CONCLUSIONS

Elevated C-reactive protein plasma levels still persisting 96 h after stent implantation might reflect a prolonged inflammatory reaction to coronary stent implantation which might causally be involved in pathophysiological mechanisms leading to restenosis.

Design and dosimetry of a novel 90Y beta source to prevent restenosis after angioplasty

PURPOSE

Post-dilatation irradiation of the vessel wall is currently under investigation for prevention of restenosis after balloon dilatation. For the irradiation, special sources were designed for animal experiments which would give equivalent irradiation conditions and doses to the vessel wall that would later be employed for human application.

METHODS AND MATERIALS

For the planned irradiations, a specially designed yttrium-wire of 0.45-mm diameter coated with a thin shrink tube to prevent contamination was deployed. Several leakage tests applied before and after application proved that the irradiation source was leakproof. Dosimetry was performed by using 0.1-mm-thick thermoluminescent dosimeters (TLD-100) calibrated against a primary standard. A shielding transport and application container was designed to facilitate the handling of the source during use, while reducing exposure of the medical personnel.

RESULTS

The designed source proves to be flexible for the insertion into proximal coronary vessels, and positioning at the site of stenosis. It provides an optimum protection of the animal and requires little radiation protection efforts on behalf of the medical staff. Dosimetric calculations and measurements showed that a centering of the source inside the vessel could be achieved with a maximum deviation of 50% between maximum and average dose levels.

CONCLUSION

A yttrium-90 beta brachytherapy source was designed which provides high flexibility within proximal coronary arteries, ensures an adequate centering inside the artery, and provides irradiation conditions to the vessel wall of the experimental animal comparable to the application inside a human artery.

[Acute coronary syndromes: physiopathology and therapeutic aspects]

This article discusses recent developments in the field of acute coronary syndromes including pathophysiological mechanisms as well as therapeutic strategies. A plaque disruption is caused by different stimuli in a plaque prone to rupture, i.e. a plaque with a lipid-rich core and high local concentration of inflammatory cells (T-cells, monocytes/macrophages, mast cells). These cells are capable of producing matrix degradation products and can reduce stability of a plaque. Thrombus formation, based on platelet activation and aggregation as well as fibrin formation, is the main consequence of plaque disruption. Depending on the degree of thrombus formation occlusion is followed clinically by unstable angina (subtotal occlusion) or by acute myocardial infarction (total occlusion). Accompanying vasoconstriction may further aggravate the situation. Principles of therapy are thrombus dissolution as well as prevention of new thrombus formation: main goals of thrombolytic therapy in acute myocardial infarction are a prompt (less than 3 hours), complete, and sustained (prevention of early thrombotic reocclusion) reperfusion.

Angiotensin-converting enzyme and angiotensin II receptor 1 polymorphism in coronary disease and malignant ventricular arrhythmias

OBJECTIVES

It has been reported that patients carrying the angiotensin-converting enzyme (ACE) deletion DD genotype with the angiotensin II type 1 (AT1) C allele are at increased risk for myocardial infarction. The frequency distribution of the ACE and AT1 receptor gene polymorphism and their possible relation regarding malignant ventricular arrhythmias in patients with coronary artery disease (CAD) and left ventricular dysfunction was determined.

METHODS

The ACE I/D and AT1 A/C polymorphisms (using polymerase chain reaction) in 100 Caucasian patients suffering from CAD with a history of malignant ventricular arrhythmias treated with an implantable cardioverter defibrillator (ICD group) was compared to 127 age-matched Caucasian patients with CAD and no history of malignant ventricular arrhythmias (control group). All patients had reduced left ventricular ejection fraction of < 40% and were comparable regarding sex distribution, body mass index, ACE-inhibitor treatment, lipid status and duration of CAD.

RESULTS

The prevalence of DD/CC in the ICD group was significantly higher (19% versus 10%, p < 0.0001). The risk for malignant ventricular arrhythmias was associated with the combination of ACE D and AT1 C alleles (odds-ratio: 2.4, 95% confidence interval 1.41 to 3.94, p < 0.001). The distribution of ACE and AT1 genotypes was not different between the two group.

CONCLUSIONS

Patients with coronary artery disease and left ventricular dysfunction carrying ACE D and AT1 C alleles are at increased risk for development of malignant ventricular arrhythmias. Because of available pharmacological inhibitors, these results may have clinical implications for the prevention of sudden cardiac death.

Predictive value of PAI-1 plasma activity and thallium perfusion imaging for restenosis after percutaneous transluminal angioplasty in clinically asymptomatic patients

BACKGROUND

The main long-term complication of percutaneous transluminal coronary angioplasty (PTCA) is restenosis that occurs in 30-50 percent of all primary successful cases. The purpose of this study was to evaluate the predictive value of changes in plasminogen activator inhibitor-1 (PAI-1) activity and of thallium dipyridamole perfusion imaging performed 3 months after successful angioplasty. All patients were asymptomatic at evaluation. The results of these two noninvasive tests were compared with the angiographic outcome after 6 months.

METHOD AND PATIENTS

Twenty-five patients were included in this prospective study. All patients had single vessel disease, successful angioplasty and were free of clinical symptoms 3 months after angioplasty that would suggest late restenosis. In 12/25 patients (48%) angiographic restenosis (percent diameter stenosis >50%) was determined by follow-up angiography 6 months after angioplasty. PAI-1 plasma activity was determined by a functional titration assay and increase or decrease of PAI-1 plasma activity was evaluated between values obtained before and 3 months after angioplasty. In 7/25 (28%) patients PAI-1 plasma activity increased to more than 90% of pre-angioplasty values. This increase correlated with angiographic restenosis evaluated 6 months after angioplasty (sensitivity 42%, specificity 85%, positive predictive value 71%, and negative predictive value 61%). T1-201-perfusion imaging was performed 3 months after angioplasty. This test was indicative for subsequent restenosis in 5/25 patients (sensitivity 33%, specificity 100%, positive predictive value 62%, and negative predictive value 100%). In 10/25 (40%) patients at least one of the two non-invasive tests performed 3 months after angioplasty predicted angiographic restenosis at 6 months: the combined use of PAI-1 and T1-201-perfusion imaging resulted in increased sensitivity (67%) and high specificity (85%).

CONCLUSION

The results of this study indicate that an increase of PAI-1 plasma activity may improve the predictive value for restenosis of T1-201-scintigraphy performed 3 months after angioplasty even in asymptomatic patients.

Predictors of outcome in patients with implantable cardioverter defibrillators

This study determined the impact of clinical characteristics on shock occurrence and survival in patients with implantable cardioverter-defibrillator (ICD).

METHODS AND RESULTS

During a follow-up of 27 +/- 18 months, the actuarial incidence of appropriate shocks in 200 consecutive patients was 18, 36 and 72% at 1, 3, and 5 years, respectively. Coronary artery disease was the only significant predictor for shock occurrence (relative risk 1.32, p = 0.03). The actuarial incidence of total mortality was 10, 17 and 33% at 1, 3, and 5 years, respectively. The most powerful predictors for total mortality were: New York Heart Association functional class (NYHA) III (relative risk 4.8, p = 0.001) and a history of congestive cardiac failure (relative risk 3.6, p = 0.01).

CONCLUSION

During long-term follow-up, the majority of patients receive appropriate shocks. No strong predictors for shock occurrence can be identified from the data analyzed. A history of congestive cardiac failure and the NYHA III are the most powerful predictors for total mortality. These clinical factors may provide valuable criteria to identify patients who will benefit from the implantation of ICD.

Therapeutic efficiency of lipoprotein(a) reduction by low-density lipoprotein immunoapheresis

This study was performed to investigate the effect of low-density lipoprotein (LDL) immunoapheresis on lipoprotein(a) [Lp(a)] reduction in patients with heterozygous and homozygous familial hyperlipidemia (N=16) and insufficient response to lipid-lowering agents. By desorption of approximately 5,700+/-500 mL of plasma, a mean reduction in total cholesterol of 62% (P < .001) and in LDL-cholesterol of 70% (P < .001) was achieved. Lp(a), which was elevated at study entry in seven of these patients (82.1+/-34.3 mg/dL; range, 48 to 148 mg/dL), was reduced during the initial LDL-apheresis procedure by 74.8%+/-14.1% (P < .001). Long-term apheresis treatment performed at weekly intervals resulted in an mean reduction in Lp(a) pretreatment values to 39.1+/-28.5 mg/dL (-54%; P < .001). Desorbed Lp(a) was measured at the waste of the columns for 31 apheresis treatments. Lp(a) concentration of the column waste was higher in patients with elevated serum Lp(a) pretreatment values as compared with those with Lp(a) serum values within the normal range (elevated Lp(a), 1,420+/-380 mg; without elevated Lp(a), 235+/-190 mg; P < .001). The rate of return of Lp(a) following apheresis treatment scheduled at weekly intervals was comparable to that of LDL-cholesterol.