Left atrial pump strain predicts long-term survival after transcatheter aortic valve implantation

BACKGROUND

This study aims at investigating left atrial (LA) deformation by left atrial reservoir (LARS) and pump strain (LAPS) and its implications for long-term survival in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI).

METHODS

Speckle tracking echocardiography was performed in 198 patients with severe AS undergoing TAVI. Association of strain parameters with cardiovascular mortality was determined.

RESULTS

Over a follow-up time of 5 years, 49 patients (24.7%) died. LAPS was more impaired in non-survivors than survivors (P = 0.010), whereas no difference was found for LARS (P = 0.114), LA ejection fraction (P = 0.241), and LA volume index (P = 0.292). Kaplan-Meier analyses yielded a reduced survival probability according to the optimal threshold for LAPS (P = 0.002). A more impaired LAPS was associated with increased mortality risk (HR 1.12 [95% CI 1.02-1.22]; P = 0.014) independent of LVEF, LAVI, age, and sex. Addition of LAPS improved multivariable echocardiographic (LVEF, LAVI) and clinical (age, sex) models with potential incremental value for mortality prediction (P = 0.013 and P = 0.031, respectively). In contrast, LARS and LAVI were not associated with mortality.

CONCLUSIONS

In patients undergoing aortic valve replacement for severe AS, LAPS was impaired in patients dying during long-term follow-up after TAVI, differentiated survivors from non-survivors, was independently associated with long-term mortality, and yielded potential incremental value for survival prediction after TAVI. LAPS seems useful for risk stratification in severe AS and timely valve replacement.

3D atrial strain for prediction of atrial fibrillation recurrence

Introduction

Atrial fibrillation (AF) is one of the most common supraventricular arrhythmias. Treatment options apart from medication include interventional catheter-guided pulmonary vein isolation (PVI). However, there is limited knowledge about factors predicting arrhythmia recurrence after PVI.

Aim

To study the association of 3-dimensional (3D) left atrial (LA) strain (LAS) and 3D electro-anatomical voltage mapping (EAVM) with early recurrence of AF after PVI.

Methods

In this prospective single center study, 93 patients undergoing PVI were enrolled between December 2018 and October 2021. All patients underwent an echocardiographic examination within two weeks before PVI using the Canon Aplio i900 system to analyse LAS from 3D LA volume. A 3D EAVM was obtained using high-density mapping catheters during PVI. The CARTO 3 system (Version V6-V7) was used for determining LA scar area by low voltage mapping (local amplitude <0.5 mV) indicated as percentage (EAVM-%). Follow-up time points were set at 2, 3, 6 and 12 months to investigate recurrence of AF, with exclusion of events occurring during the first two months (blanking phase).

Results

During follow-up, 12 out of 93 patients experienced recurrence of AF (12.9%; AF-Group). Baseline characteristics did not differ between AF-Group and Non-AF-Group. In contrast, LAS was significantly impaired in the AF-Group (median −4.6, IQR [−5.6 to −3.6]) when compared to the Non-AF-Group (−6.2 [−8.3 to −4.5]; p=0.009). The EAVM-% did not differ between the groups (AF-Group: 5.0 [1.5 to 21.5]; Non-AF-Group: 4.4 [1.5 to 15.9]; p=0.710). No significant correlations were found between LAS and EAVM-% (r=0.03, p=0.812). A cut-off value of −5.89% for LAS had a sensitivity of 100% and a specificity of 57% for AF recurrence (AUC=70%; p<0.001). Kaplan Meier curves for event-free survival were generated based on the LAS cut-off demonstrating excellent differentiation of those with and without AF recurrence (p<0.001; see figure). Furthermore, LAS was associated with an increased risk of early AF recurrence (HR 1.40, IQR [1.02–1.92], p=0.040), while EAVM-% was not (HR 0.99 [0.95–1.04], p=0.787).

Conclusion

3D LAS was associated with an increased risk of early AF recurrence after PVI, while EAVM-% was not. 3D LAS might be used for identifying patients who would benefit from PVI.

Funding Acknowledgement

Type of funding sources: None.

Right ventricular versus left ventricular global longitudinal strain for association with all-cause mortality after transcatheter aortic valve implantation

Introduction

Speckle-tracking echocardiography plays an increasingly important role in the assessment of aortic stenosis (AS), the most common valvular heart disease in the Western population. Right ventricular (RV) and left ventricular (LV) global longitudinal strain (GLS) were studied for their association with all-cause mortality in AS patients undergoing transcatheter aortic valve implantation (TAVI).

Purpose

To investigate whether simultaneous assessment of RV and LV GLS provides a better association with all-cause mortality during long-term follow-up after TAVI.

Methods

In our prospective registry we identified 109 patients with severe AS who underwent TAVI and had a pre-procedural echocardiography within three months of the procedure allowing complete assessment of RV and LV GLS using TomTec Image Arena. All-cause mortality was defined as endpoint.

Results

RV GLS was lower among non-survivors (N=36; median [IQR]: −13.94 [−16.31 to −12.62]; p<0.001) than survivors (N=73; −17.04 [−20.16 to −15.22]; p<0.001), while LV GLS did not differ (p=0.249). RV GLS >−16.6% differentiated survivors from non-survivors (sensitivity 78%; specificity 63%; ROC AUC 71%; p<0.001), while LV GLS did not (p=0.243). Kaplan Meier curves showed good differentiation of survivors and non-survivors with the RV GLS (p<0.001; Figure 1), but not the LV GLS cut-off (p=0.058). In univariable Cox regression models, RV GLS was associated with all-cause mortality (HR 1.10 [95% CI 1.02 to 1.18]; χ2=6.64; p=0.01), while LV GLS was not (HR 1.05 [0.96 to 1.16]; χ2=1.08; p=0.299). In bivariable models, association of RV GLS with all-cause mortality was independent of LV GLS or LV ejection fraction (LVEF; Table 1). ANOVA likelihood ratios revealed that inclusion of RV GLS to LV GLS or LVEF improved their model fitness, while that of LV GLS did not (Table).

Conclusion

RV GLS was associated with all-cause mortality after TAVI, while LV GLS and LVEF were not. The association of RV GLS was independent of LV GLS and LVEF and showed potential incremental value for assessment of outcome association, while LV GLS did not.

Funding Acknowledgement

Type of funding sources: None.

Association of left ventricular myocardial work with all-cause mortality after transcatheter aortic valve implantation

Introduction

Echocardiography is an important modality for peri-interventional assessment of patients undergoing transcatheter aortic valve implantation (TAVI). Left ventricular (LV) global longitudinal strain measures ventricular deformation at end-systole, while myocardial work parameters determine LV deformation throughout the cardiac cycle and correct for afterload.

Aims

To evaluate LV deformation by myocardial work efficiency (GWE) and index (GWI) in early post-TAVI echocardiography and explore its association with all-cause mortality.

Methods

We analyzed 144 patients with severe aortic stenosis and an echocardiography study within two weeks after TAVI. All echocardiographic analyses were performed using GE EchoPac v2.6. Follow-up data was obtained from medical records until September 2021. All-cause mortality was the primary endpoint.

Results

During a median follow-up duration of 625 [IQR: 511.0–769.8] days, 25 (17.5%) patients died. No significant differences in the baseline characteristics were found between non-survivors and survivors. GWE (Figure 1A) and GWI (Figure 1B) were significantly lower among non-survivors than survivors. Both myocardial work parameters differentiated non-survivors from survivors with a cut-off value of −85% for GWE and 990 mmHg% for MWI (Figure 2; both p<0.001).

Conclusions

In this study, GWE and GWI were lower among non-survivors than survivors and were associated with an increased risk of all-cause mortality after TAVI.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swiss Heart Foundation

Sex-specific difference in cardiac function in patients with systemic sclerosis: association with cardiovascular outcomes

Background

Cardiac involvement is an important cause of hospitalization and mortality in patients with systemic sclerosis (SSc) and advanced echocardiographic measures such as left ventricular (LV) global longitudinal strain (GLS) have already demonstrated to improve risk-stratification. However, possible sex differences in echocardiographic parameters including LV GLS have not been explored so far.

Purpose

To compare standard and advanced echocardiographic parameters between men and women with SSc and evaluate their association with cardiovascular outcomes.

Methods

A total of 746 SSc patients from four different centers were included of which 628 (84%, 54±13 years) women and 118 (16%, 55±15 years) men. Baseline transthoracic echocardiographic (TTE) data with standard and advanced (LV GLS) measurements as well as clinical characteristics were analysed. The study endpoint was the composite of all-cause mortality and cardiovascular hospitalisations.

Results

Men and women showed several differences in terms of disease characteristics: greater modified Rodnan skin score, higher prevalence of diffuse cutaneous SSc, lung fibrosis and myositis, more impaired pulmonary function (DLCO) and higher creatine phosphokinase were observed in men, while women were characterized by longer disease duration, higher NT-proBNP and lower glomerular filtration rate. By TTE, men showed larger LV indexed volumes, lower LV ejection fraction and more impaired LV GLS [−19% (IQR −20% to −17%) vs. −21% (IQR: −22% to −19%, p<0.001)]. Considering the significant differences in clinical characteristics between men and women, a propensity matching score was applied to explore whether sex-differences in TTE parameters were maintained. The matching was performed according to age, disease duration, presence of diffuse SSc, lung fibrosis, DLCO and NT-proBNP (n=140); after matching, LV GLS still showed significant difference between men and women [−19% (IQR −20% to −18%) vs. −20% (IQR −22% to −18%, p=0.03)] while LV volumes and ejection fraction did not. After a median follow-up of 48 months (IQR: 26–80), the combined endpoint occurred in 182 patients and Kaplan-Meier survival analysis (Figure) showed that men experienced higher cumulative event rates as compared to women (Chi-square 8.648; Log rank 0.003) even after matching for clinical characteristics (Chi-square 7.211; Log rank 0.007); however, sex difference in outcomes was neutralized after matching groups according to LV GLS. Furthermore, LV GLS showed a significant association with prognosis in the overall group (HR: 1.173; 95% CI: 1.106–1.244, p<0.001) without significant interaction with sex (p=0.373), indicating a consistent prognostic value of LVGLS for both men and women.

Conclusions

Among patients with SSc, LV GLS is more impaired in men as compared to women even after matching for clinical characteristics, and its impairment is associated with higher prevalence of death and cardiovascular hospitalization.

Funding Acknowledgement

Type of funding sources: None.

A novel diagnostic score to differentiate between athlete"s heart and ARVC

Funding Acknowledgements

Type of funding sources: None.

Background

The 2010 Task Force Criteria (TFC), although representing the current gold standard to diagnose arrhythmogenic right ventricular cardiomyopathy (ARVC), have not been tested to differentiate ARVC from the athlete’s heart. Furthermore, not all 6 diagnostic categories are easy to obtain.

Purpose

We hypothesized that atrial dimensions are useful to differentiate between both entities. Therefore, we developed a new diagnostic score based upon readily available clinical parameters including atrial dimensions on TTE to help distinguishing the athlete’s heart from ARVC in daily clinical practice.

Methods

In this observational study, 37 patients with definite ARVC (from the Zurich ARVC Program) were compared to 68 athletes. Base on ROC analysis, the following echocardiographic, laboratory and electrocardiographic parameters were included in the final score: indexed right/left atrial volumes (RAVI/LAVI ratio), NT-proBNP, RVOT measurements (PLAX and PSAX adjusted for BSA) on TTE, tricuspid annular motion velocity (TAM) on TTE, precordial electrocardiographic T-wave inversions and depolarization abnormalities according to the TFC.

Results

ARVC patients had a higher RAVI/LAVI ratio (1.78 ± 1.6vs0.95 ± 0.3,p < 0.001), lower right-ventricular function (fac:28 ± 9.7vs42.1 ± 4.8%,p < 0.001; TAM:17.9 ± 5.6vs23.3 ± 3.7mm,p < 0.001) and higher serum NT-proBNP levels (491 ± 771vs44.8 ± 50.6ng/l,p < 0.001). Our novel score outperformed the performance of the 2010 TFC using those parameters, which are available in routine clinical practice (AUC95%,p < 0.001(95%CI.91-.99)vs.AUC90%,p < 0.001(95%CI.84-.97). A score value of 7/12 points yielded a specificity of 98% and a sensitivity of 61% for a diagnosis of ARVC.

Conclusions

ARVC patients present with significantly larger RA as compared to athletes, resulting in a greater RAVI/LAVI ratio. Our novel diagnostic score includes readily available clinical parameters and has a high diagnostic accuracy to differentiate between ARVC and the athlete´s heart. Abstract Figure. Novel clinical score

Mitral annular disjunction in patients with severe aortic stenosis: Extent and reproducibility of measurements with computed tomography

•

Mitral annulus disjunction (MAD) is frequent in patients with severe aortic stenosis.

•

Computed tomography enables a highly reproducible assessment of MAD.

•

MAD patients significantly more often have mitral valve prolapse.

Objectives

To determine with CT the prevalence and extent of mitral annular disjunction (MAD) in patients undergoing transcatheter aortic valve replacement (TAVR) and its association with mitral valve disease and arrhythmia.

Methods

We retrospectively evaluated 408 patients (median age, 82 years; 186 females) with severe aortic stenosis undergoing ECG-gated cardiac CT with end-systolic data acquisition. Baseline and follow-up data were collected in the context of a national registry. Two blinded, independent observers evaluated the presence of MAD on multi-planar reformations. Maximum MAD distance (left atrial wall-mitral leaflet junction to left ventricular myocardium) and circumferential extent of MAD were assessed on CT using dedicated post-processing software. Associated mitral valve disease was determined with echocardiography.

Results

7.8 % (32/408) of patients with severe aortic stenosis had MAD. The maximum MAD was 3.5 mm (interquartile range: 3.0–4.0 mm). The circumferential extent of MAD comprised 34 ± 15 % of the posterior and 26 ± 12 % of the entire mitral annulus. Intra- and interobserver agreement for the detection of MAD on CT were excellent (kappa: 0.90 ± 0.02 and 0.92 ± 0.02). Mitral regurgitation (p = 1.00) and severe mitral annular calcification (p = 0.29) were similarly prevalent in MAD and non-MAD patients. Significantly more patients with MAD (6/32; 19 %) had mitral valve prolapse compared to those without (6/376; 2 %; p < 0.001). MAD was not associated with arrhythmia before and after TAVR (p > 0.05).

Conclusions

Using CT, MAD was found in 7.8 % of patients with severe aortic stenosis, with a higher prevalence in patients with mitral valve prolapse. We found no association of MAD with arrhythmia before or after TAVR.

Sex difference in left ventricular global longitudinal strain in patients with systemic sclerosis: association with outcomes

Background

Cardiac involvement is an important cause of hospitalization and mortality in patients with systemic sclerosis (SSc). Advanced echocardiographic measures such as global longitudinal strain (GLS) have already demonstrated to help identifying cardiac involvement and improve risk-stratification in these patients. However, possible sex differences in echocardiographic parameters including GLS have not been explored so far.

Purpose

To compare standard and advanced (GLS) echocardiographic parameters between male and female patients with SSc and evaluate their association with cardiovascular outcomes.

Methods

A total of 408 patients (345 females, 54±14 years old and 63 males 51±13 years old) were included in the study. The study endpoint was all-cause mortality combined with hospitalisations for heart failure, myocardial infarction, coronary interventions, device implantations, arrhythmias, cerebral infarction and peripheral ischemic disease.

Results

Males and females were comparable in terms of cardiovascular risk-factors and comorbidities but showed differences in terms of disease characteristics: greater modified rodnan skin score and higher creatine phosphokinase was observed in males as compared to females, although high NT-proBNP and deteriorated glomerular filtration rate was more prevalent in females. By standard echocardiography, male SSc patients were characterised by greater left ventricular (LV) volumes, but no difference was observed in LV ejection fraction. By advanced echocardiographic analysis, LV GLS was more preserved in female patients (−21% (IQR: −22% to −20%) as compared to males (−20% (IQR −21% to −19%), p&lt;0.001. After median follow-up of 39 months (IQR: 22–66), the combined endpoint occurred in 84 patients, males were affected significantly more frequently as compared to females (20 (32%) vs. 64 (19%), p=0.017). Kaplan-Meier survival analysis showed that impaired LV GLS (based on median value −20%) was associated with higher cumulative rates of all-cause mortality both in males and females with SSc (females: Chi-Square = 80.307 Log Rank &lt;0.001; males: Chi-Square = 4.493 Log Rank = 0.034) (Fig. 1). In univariate cox regression analyses, LV GLS was also significantly associated with the endpoint both in males and females (in males HR: 1.291, 95% CI: 1.033–1.612, p=0.025, in females HR: 1.386, 95% CI: 1.290–1.491, p&lt;0.001).

Conclusions

Our study shows that among patients with SSc, LV GLS is more impaired in males as compared to females but in both groups is associated with higher prevalence of death and cardiovascular hospitalization.

Funding Acknowledgement

Type of funding source: None

Mitral annular calcification in the elderly - Quantitative assessment

PURPOSE

To determine the reliability of subjective and objective quantification of mitral annular calcification (MAC) in elderly patients with severe aortic stenosis, to define quantitative sex- and age-related reference values of MAC, and to correlate quantitative MAC with mitral valve disease.

METHODS

In this retrospective, IRB-approved study, we included 559 patients (268 females, median age 81 years, inter-quartile range 77-85 years) with severe aortic stenosis undergoing CT. Four independent readers performed subjective MAC categorization as follows: no, mild, moderate, and severe MAC. Two independent readers performed quantitative evaluation of MAC using the Agatston score method (Agatston_MAC). Mitral valve disease was determined by echocardiography.

RESULTS

Subjective MAC categorization showed high inter-reader agreement for no (k ​= ​0.88) and severe MAC (k ​= ​0.75), whereas agreement for moderate (k ​= ​0.59) and mild (k ​= ​0.45) MAC was moderate. Intra-reader agreement for subjective MAC categorization was substantial (k ​= ​0.69 and 0.62). Inter- and intra-reader agreement for Agatston_MAC were excellent (ICC ​= ​0.998 and 0.999, respectively), with minor inconsistencies in MAC involving the left ventricular outflow tract/aortic valve. There were significantly more women than men with MAC (n ​= ​227, 85% versus n ​= ​209, 72%; p ​< ​0.001), with a significantly higher Agatston_MAC (median 597, range 81-2055 versus median 244; range 0-1565; p ​< ​0.001), particularly in patients ≥85 years of age. Agatston_MAC showed an area-under-the-curve of 0.84 to diagnose mitral stenosis, whereas there was no association of Agatston_MAC with mitral regurgitation (p ​> ​0.05).

CONCLUSIONS

Our study in elderly patients with severe aortic stenosis shows that quantitative MAC scoring is more reliable than subjective MAC assessment. Women show higher Agatston_MAC scores than men, particularly in the elderly population. Agatston_MAC shows high accuracy to diagnose mitral stenosis.

A Prospective Pilot Study to Identify a Myocarditis Cohort who may Safely Resume Sports Activities 3 Months after Diagnosis

International cardiovascular society recommendations to return to sports activities following acute myocarditis are based on expert consensus in the absence of prospective studies. We prospectively enrolled 30 patients with newly diagnosed myocarditis based on clinical parameters, laboratory measurements and cardiac magnetic resonance imaging with mildly reduced or preserved left ventricular ejection fraction (LVEF) with a follow-up of 12 months. Cessation of physical activity was recommended for 3 months. The average age was 35 (19-80) years with 73% male patients. One case of non-sustained ventricular tachycardia was recorded during 48-h-Holter electrocardiogram. Except for this case, all patients were allowed to resume physical exercise after 3 months. At 6- (n = 26) and 12-month (n = 19) follow-up neither cardiac events nor worsening LVEF were recorded. The risk of cardiac events at 1 year after diagnosis of myocarditis appears to be low after resumption of exercise after 3 months among patients who recover from acute myocarditis.

P1842Impact of left ventricular outflow tract sphericity on transcatheter heart valve hemodynamics and outcome after transcatheter aortic valve implantation

Background

Accurate assessment of aortic annulus and left ventricular outflow tract (LVOT) anatomy is mandatory for appropriate device selection in order to achieve optimal deployment of transcatheter heart valves (THV).

Aim

To evaluate the impact of LVOT shape as determined by the sphericity index (ratio of long and short LVOT diameter) on THV hemodynamics.

Methods

1000 consecutive patients diagnosed with severe symptomatic aortic stenosis and undergoing TAVI between May 2008 and July2017 were analyzed. Assessment of aortic root dimensions including the LVOT was performed by contrast-enhanced multidetector computed tomography (MDCT) in all patients. The primary endpoint was 30-day device success as defined by the VARC-2 criteria. Secondary endpoints included all-cause mortality, cardiovascular mortality, permanent pacemaker implantation (PPI), and a 30-day combined early safety endpoint (all-cause mortality, all strokes, life threatening bleeding, acute kidney injury stage 2 or 3, CAD obstruction requiring intervention, major vascular complication, valve related dysfunction requiring repeat intervention).

Results

Patients were divided into 3 groups according to LVOT sphericity index (SI) quartiles. The three groups (low-SI: 0.4–0.63, n=250; mid-SI: 0.64–0.75, n=500; high-SI: 0.76–1.0, n=250) were well balanced in terms of baseline characteristics, except for gender distribution with more female patients in the low-SI group (36.8% vs. 49.0% vs. 60.0%; p=0.ehz748.05941). Assessment of calcification volume and Agatston score demonstrated significantly higher aortic valve and LVOT calcification in the high-SI group. The primary endpoint of device success after 30-days did not differ between the 3 groups (92.4% vs 91.9% vs. 87.9%; p=NS). However, moderate or severe paravalvular regurgitation (PAR) occurred significantly more often in the high-SI as compared to the other groups (4.1% vs. 5.2% vs. 10.6%; p=0.004 for low-SI vs. high-SI). In contrast, PPI rates, the early safety endpoint at 30 days, and all-cause mortality at 1 year did not differ between the groups. In the high-SI group implantation of a BE valve was associated with a significantly higher rate of device success as compared to SE valves (93.8% vs. 82.2%, p=0.007). This difference was driven by a higher rate of moderate or severe PAR (6.9% vs. 15.3%, p=0.007) in patients treated with SE valves. Moreover, patients in the high-SI group receiving a SE valve required more often a PPI than those treated with a BE valve (26.2% vs 13.3%, p=0.012). There was no difference between the THV types in the other SI groups in terms of primary and secondary endpoints.

Conclusion

A more circular LVOT is associated with higher aortic valve and LVOT calcification. Implantation of a SE THV results in higher rates of moderate or severe PAR and persistent conduction disorder requiring PPI in such patients.

P5276A prospective pilot study to identify a myocarditis cohort who may safely resume sports activities 3 months after diagnosis

Background

Sports activities may promote arrhythmias in the setting of acute myocarditis. International cardiovascular society recommendations to return to sports activities following acute myocarditis are based on expert consensus in the absence of prospective studies.

Purpose

We sought to identify patients who may safely resume sports activities 3 months after acute myocarditis.

Methods

We prospectively enrolled 27 patients with newly diagnosed myocarditis based on clinical parameters, elevated high sensitive troponin (TnT-hs) and cardiac magnetic resonance imaging (CMR) with mildly reduced or preserved LVEF. Follow-up examination included laboratory findings, electrocardiogram (ECG), 48-hour-Holter ECG, echocardiography, exercise stress testing and CMR. Cessation of physical activity was recommended for 3 months. All patients were followed for cardiac events for 12 months.

Results

Average age was 35 (19–80) years with 73% male patients. All patients performed 3- and 6-month follow-up with above mentioned diagnostic tests. Eight patients did not present for 12-month follow-up, but were contacted by phone. No cardiac events occurred within the interval of 12 months.

After 3 months, participants achieved an average of 92% of predicted maximum power on stress test. One case of non-sustained ventricular tachycardia was recorded during 48-hour-Holter ECG. Except for this case, all patients were allowed to resume physical exercise after 3 months. At 6- (n=26) and 12-month (n=19) follow-up no arrhythmias, recurrent myocarditis, worsening left ventricular ejection fraction (LVEF) or physical performance were recorded. TnT-hs, creatine kinase (CK), myoglobin (Mb), and C-reactive protein (CRP) normalized.

Conclusion

The risk of cardiac events and decreasing LVEF appears to be low after early resumption of exercise in asymptomatic patients who recover from acute myocarditis.

Acknowledgement/Funding

Forschungskredit of the University of Zurich,the Holcim Foundation, the Hartmann Müller Foundation, and the Walter and Gertrud Siegenthaler Foundation

P2270Clinical characteristics and outcomes after TAVI in patients reclassified to moderate aortic stenosis by integration of multimodality imaging and pressure recovery

Background

Accurate assessment of aortic stenosis (AS) severity is critical for the correct management of patients. This has become particularly important because the introduction of transcatheter aortic valve implantation (TAVI) has markedly increased the number of patients eligible for aortic valve replacement

Aims

To assess whether reclassification of aortic stenosis (AS) grading by integration of fusion imaging using data from transthoracic echocardiography (TTE) and multidetector computed tomography (MDCT) under consideration of the energy loss index (ELI) predicts outcome in patients undergoing transcatheter aortic valve implantation (TAVI).

Methods

197 consecutive patients with symptomatic severe AS undergoing TAVI at our University Heart Center were included in this study. AS severity was determined according to current guidelines.

Results

Left ventricular outflow tract (LVOT) area derived from TTE was smaller than the planimetric area in MDCT due the ovoid shape of the LVOT (3.4±0.12 cm2 vs. 4.5±0.23 cm2; p<0.01). The sinotubular junction (ST-junction) diameter measured in TTE was similar to maximal, minimal, and mean diameters determined by MDCT. The sphericity index confirmed an almost circular anatomy of ST-junction, and its area derived from TTE was similar to the planimetric area in MDCT. Fusion aortic valve area index (fusion AVAi) assessed by inserting MDCT derived planimetric LVOT area in the continuity equation was significantly higher in all patients compared to conventional AVAi. 62 patients were reclassified from severe to moderate AS because fusion AVAi was >0.6 cm2/m2. ELI was calculated for conventional AVAi and fusion AVAi each with ST-junction area determined by both TTE and MDCT. Calculating ELI with fusion AVAi resulted in significantly larger effective orifice area, with values >0.6 cm2/m2 in 83 patients (ST-junction area from echo) and 85 patients (ST-junction area from MDCT). Similarly, calculating ELI with conventional AVAi resulted in significantly larger effective orifice area as compared to AVAi alone. Reclassified patients had lower mean transvalvular pressure gradients, lower myocardial mass, less symptoms according to NYHA classification, and lower proBNP levels at baseline. While both groups exhibited improvement of functional status at 1 year of follow-up, the survival rate at 3 years after TAVI was higher in patients reclassified to moderate AS (81% versus 66%; p=0.02).

Conclusion

Integration of TTE and MDCT derived values for calculation of ELI reclassifies the severity of AS in 43% of patients initially diagnosed with severe AS.Although reclassified patients display less advanced valve disease at baseline, TAVI results in functional improvement in all patients. Furthermore, patients reclassified to moderate AS exhibit higher survival rates at 3 years after aortic valve replacement.

P3689Association of echocardiographic progression and genetic profile in arrhythmogenic right ventricular cardiomyopathy

Background

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is frequently associated with mutations in genes coding for desmosomal proteins. In this study, we investigated the association of genetic status with ARVC progression as defined by echocardiographic parameters.

Methods

We tested 62 ARVC patients for their genetic profile. Accordingly, they were grouped in mutation positive (48 (77%) patients; median age 48.5 years; 33 (69%) males), and mutation negative (14 (23%) patients; median age 45 years; 10 (71%) males). Prevalent mutations were Desmoglein-2 (DSG2) in 16 (26%), Desmoplakin (DSP) in 14 (23%), and Plakophilin-2 (PKP2) in 9 (15%) patients.

Results

At baseline, there were no significant differences in clinical characteristics between the two groups. Patients were followed-up for a median time period of 1420 days, and there was no significant difference in the duration of follow-up between the two groups (p=0.05).

In the mutation positive group, there was a significant increase in right ventricular end-diastolic area (p=0.002), right atrial short (p=0.008) and long (p=0.002) diameter, left atrial diameter (p=0.014), and a decrease in left ventricular ejection fraction (p=0.014) during follow up. Right ventricular functial parameters did not change significantly (tricuspid annular plane systolic excursion: p=0.24; fractional area change: p=0.088).

In the mutation negative group, none of the aforementioned echocardiographic findings exhibited any significant difference during follow-up: right ventricular end-diastolic area (p=0.1); right atrial short (p=0.7) and long (p=0.9) diameter, left atrial diameter (p=0.6), and left ventricular ejection fraction (p=0.3). Similarly, right ventricular functional parameters did not change significantly (tricuspid annular plane systolic excursion: p=0.77; fractional area change: p=0.80. Results are summarized in the figure.

Change in echocardiographic findings.

Conclusions

There is a strong association between echocardiographic progression of ARVC phenotype and the presence of a pathogenic mutation. Such mutations should be searched in all patients with an ARVC phenotype, and mutation positive individuals should be followed-up in shorter intervals.

Amiodarone inhibits arterial thrombus formation and tissue factor translation

BACKGROUND

In patients with coronary artery disease and reduced ejection fraction, amiodarone reduces mortality by decreasing sudden death. Because the latter may be triggered by coronary artery thrombosis as much as ventricular arrhythmias, amiodarone might interfere with tissue factor (TF) expression and thrombus formation.

METHODS AND RESULTS

Clinically relevant plasma concentrations of amiodarone reduced TF activity and impaired carotid artery thrombus formation in a mouse photochemical injury model in vivo. PTT, aPTT, and tail bleeding time were not affected; platelet number was slightly decreased. In human endothelial and vascular smooth muscle cells, amiodarone inhibited tumor necrosis factor (TNF)-alpha and thrombin-induced TF expression as well as surface activity. Amiodarone lacking iodine and the main metabolite of amiodarone, N-monodesethylamiodarone, inhibited TF expression. Amiodarone did not affect mitogen-activated protein kinase activation, TF mRNA expression, and TF protein degradation. Metabolic labeling confirmed that amiodarone inhibited TF protein translation.

CONCLUSIONS

Amiodarone impairs thrombus formation in vivo; in line with this, it inhibits TF protein expression and surface activity in human vascular cells. These pleiotropic actions occur within the range of amiodarone concentrations measured in patients, and thus may account at least in part for its beneficial effects in patients with coronary artery disease.

Prothrombotic gene expression profile in vascular smooth muscle cells of human saphenous vein, but not internal mammary artery

BACKGROUND

The resistance of internal mammary artery (IMA) toward thrombotic occlusion and accelerated atherosclerosis is not well understood. This study analyzed gene expression profiles of vascular smooth muscle cells (VSMCs) from IMA versus saphenous vein (SV).

METHODS AND RESULTS

54'675 probe sets were examined by Affymetrix microarrays. Thirty-one genes belonged to the coagulation system; 2 were differentially expressed, namely tissue factor (TF) and tissue-type plasminogen activator (tPA). TF was 3.1-fold lower in IMA than SV (P=0.006), whereas tPA was 9.0-fold higher (P<0.001). TF mRNA expression was lower in IMA than SV (P<0.05); tPA was higher (P<0.001). TF protein expression was 4.2+/-0.5-fold lower in IMA than SV (P<0.001); tPA was 2.6+/-0.4-fold higher (P<0.01). In IMA VSMC supernatant, TF protein and activity was lower (P<0.05), TFPI and tPA protein higher (P<0.05 and P<0.005), and clotting time of human plasma prolonged (P<0.05) as compared to SV. Migration to TF/FVIIa (10(-9) mol/L) was 3-fold lower in IMA than SV (P=0.01); PAR-2 protein expression was similar (P=NS), PAR-2 blockade without effect (P=NS).

CONCLUSIONS

Among the genes of the coagulation system, TF and tPA are differentially expressed in VSMCs from IMA versus SV. This is consistent with protection of IMA from thrombus formation and vascular remodeling.

[Echinococcus multilocularis in Grisons: distribution in foxes and presence of potential intermediate hosts]

The southern border of the European endemic area of Echinococcus multilocularis runs along the alpine crest. This endemic transition area was analysed in the canton Grisons on a small spatial scale. A total of 543 foxes originating from 10 areas north and 4 areas south of the main alpine divide were investigated. Parasites were isolated using the sedimentation and counting technique on intestinal contents. The mean prevalence of E. multilocularis was 6.4% with significant differences between different areas. In the southern valleys, only foxes from the Val Müstair were infected (14.3%). On the northern side of the main alpine divide, prevalences varied between 0 and 40%. The predation habits of foxes on potential intermediate hosts was investigated by means of stomach content analyses (n=530). Rodents of the genera Microtus/Pitymys were found in 19.6% of fox stomachs, Clethrionomys glareolus in 8.0% and Arvicola terrestris in 0.4%. A small scale analysis based on a 10 x 10 km grid suggested that the predation rate on the genera Microtus/Pitymys significantly correlated with the prevalence of E. multilocularis in foxes (Spearman's r = 0.51). Hence, E. multilocularis appears to occur in the alpine study area on a very small spatial scale. These local sources of infection may persist for decades. This may partly explains why, during the last 34 years, some human cases of alveolar echinococcosis occurred in areas of the Canton Grisons where the parasite is presently endemic in foxes. No such human cases have been recorded in other areas free of E. multilocularis.

Histamine differentially interacts with tumor necrosis factor-alpha and thrombin in endothelial tissue factor induction: the role of c-Jun NH2-terminal kinase

BACKGROUND

Histamine plays an important role in vascular disease. Tissue factor (TF) expression is induced in vascular inflammation and acute coronary syndromes.

OBJECTIVES

This study examined the effect of histamine on tumor necrosis factor-alpha- (TNF-alpha-) vs. thrombin-induced endothelial TF expression.

METHODS AND RESULTS

Histamine (10(-8)-10(-5) mol L-1), TNF-alpha (5 ng mL-1), and thrombin (1 U mL-1) induced TF expression in human endothelial cells. Although TF expression by TNF-alpha and thrombin was identical, histamine augmented TNF-alpha-induced expression 7.0-fold, but thrombin-induced expression only 2.6-fold. Similar responses occurred with TF activity. The H1-receptor antagonist mepyramine abrogated these effects. Differential augmentation by histamine was also observed at the mRNA level. Histamine-induced p38 activation preceded a weak second activation to both TNF-alpha and thrombin. Histamine-induced c-Jun NH2-terminal kinase (JNK) activation was followed by a strong second activation to TNF-alpha, and less to thrombin. Selective inhibition of this second JNK activation by SP600125 reduced TF induction to histamine plus TNF-alpha by 67%, but to histamine plus thrombin by only 32%. Histamine augmented TNF-alpha- and thrombin-induced vascular cell adhesion molecule 1 (VCAM-1) expression to a similar extent. Consistent with this observation, VCAM-1 induction to TNF-alpha and thrombin was mediated by p38, but not by JNK.

CONCLUSIONS

Histamine differentially augments TNF-alpha- vs. thrombin-induced TF expression and activity, which is mediated by the H1-receptor, occurs at the mRNA level, and is related to differential JNK activation.

Differential effects of the cyclin-dependent kinase inhibitors p27(Kip1), p21(Cip1), and p16(Ink4) on vascular smooth muscle cell proliferation

BACKGROUND

The cyclin-dependent kinase inhibitors (CKIs) have different patterns of expression in vascular diseases. The Kip/Cip CKIs, p27(Kip1) and p21(Cip1), are upregulated during arterial repair and negatively regulate the growth of vascular smooth muscle cells (VSMCs). In contrast, the Ink CKI, p16(Ink4), is not expressed in vascular lesions. We hypothesized that a variation in the inactivation of cdk2 and cdk4 during the G(1) phase of the cell cycle by p27(Kip1), p21(Cip1), and p16(Ink4) leads to different effects on VSMC growth in vitro and in vivo.

METHODS AND RESULTS

The expression of p27(Kip1) and p21(Cip1) in serum-stimulated VSMCs inactivated cdk2 and cdk4, leading to G(1) growth arrest. p16(Ink4) inhibited cdk4, but not cdk2, kinase activity, producing partial inhibition of VSMC growth in vitro. In an in vivo model of vascular injury, overexpression of p27(Kip1) reduced intimal VSMC proliferation by 52% (P<0.01) and the intima/media area ratio by 51% (P<0.005) after vascular injury and gene transfer to pig arteries, when compared with control arteries. p16(Ink4) was a weak inhibitor of intimal VSMC proliferation in injured arteries (P=NS), and it did not significantly reduce intima/media area ratios (P=NS), which is consistent with its minor effects on VSMC growth in vitro.

CONCLUSIONS

p27(Kip1) and p21(Cip1) are potent inhibitors of VSMC growth compared with p16(Ink4) because of their different molecular mechanisms of cyclin-dependent kinase inhibition in the G(1) phase of the cell cycle. These findings have important implications for our understanding of the pathophysiology of vascular proliferative diseases and for the development of molecular therapies.

Nitric oxide modulates expression of cell cycle regulatory proteins: a cytostatic strategy for inhibition of human vascular smooth muscle cell proliferation

BACKGROUND

We examined the effect of NO on the proliferation and cell cycle regulation of human aortic vascular smooth muscle cells (VSMCs).

METHODS AND RESULTS

The NO donor diethylenetriamineNONOate (10(-5) to 10(-3) mol/L) inhibited proliferation in response to 10% fetal calf serum (FCS) and 100 ng/mL platelet-derived growth factor-BB in a concentration-dependent manner. This effect was not observed with disintegrated diethylenetriamineNONOate or with the parent compound, diethylenetriamine. Adenoviral transfection of endothelial NO synthase (NOS) inhibited proliferation in response to FCS, which was prevented with N(G)-nitro-L-arginine methyl ester. NOS overexpression did not inhibit proliferation in response to platelet-derived growth factor, although the transfection efficiency and protein expression were similar to those of FCS-stimulated cells. Nitrate release was selectively enhanced from FCS-treated cells, indicating that NOS was activated by FCS only. NO caused G(1) cell cycle arrest. Cytotoxicity was determined with trypan blue exclusion, and apoptosis was assessed with DNA fragmentation. Cyclin-dependent kinase 2 expression level, threonine phosphorylation, and kinase activity were inhibited. Cyclin A expression was blunted, whereas cyclin E remained unchanged. p21 expression was induced, and p27 remained unaltered. The effect on cyclin A and p21 started within 6 hours and preceded the changes in cell cycle distribution. Proliferation in response to 10% FCS was barely inhibited with 8-bromo-cGMP (10(-3) mol/L) but was blunted with both forskolin and 8-bromo-cAMP. Proliferation in response to 2% FCS was inhibited with 8-bromo-cGMP, but it did not mimic the cell cycle effects of NO.

CONCLUSIONS

NO inhibits VSMC proliferation by specifically changing the expression and activity of cell cycle regulatory proteins, which may occur independent of cGMP. Adenoviral overexpression of endothelial NOS represents a cytostatic strategy for gene therapy of vascular disease.

Connective tissue growth factor induces apoptosis in human breast cancer cell line MCF-7

Connective tissue growth factor (CTGF) is a member of an emerging CCN gene family that is implicated in various diseases associated with fibro-proliferative disorder including scleroderma and atherosclerosis. The function of CTGF in human cancer is largely unknown. We now show that CTGF induces apoptosis in the human breast cancer cell line MCF-7. CTGF mRNA was completely absent in MCF-7 but strongly induced by treatment with transforming growth factor beta (TGF-beta). TGF-beta by itself induced apoptosis in MCF-7, and this effect was reversed by co-treatment with CTGF antisense oligonucleotide. Overexpression of CTGF gene in transiently transfected MCF-7 cells significantly augmented apoptosis. Moreover, recombinant CTGF protein significantly enhanced apoptosis in MCF-7 cells as evaluated by DNA fragmentation, Tdt-mediated dUTP biotin nick end-labeling staining, flow cytometry analysis, and nuclear staining using Hoechst 33258. Finally, recombinant CTGF showed no effect on Bax protein expression but significantly reduced Bcl2 protein expression. Taken together, these results suggest that CTGF is a major inducer of apoptosis in the human breast cancer cell line MCF-7 and that TGF-beta-induced apoptosis in MCF-7 cells is mediated, in part, by CTGF.

[Gene therapy in heart diseases]

Cardiovascular diseases are the most important cause of death and hospitalisation in industrialised countries. Although pharmacological, interventional and surgical therapy has achieved major progress during the past 25 years, most therapeutic measures are only transiently effective or require life-long medication. Molecular cardiology aims at applying molecular biological methods for both diagnosis and treatment of cardiovascular disease. With respect to diagnosis of cardiac diseases such as hypertrophic cardiomyopathy or the long QT syndrome, it has become possible to characterise mutations in the genome responsible for the disease process. It is interesting that different mutations inducing hypertrophic cardiomyopathy are associated with a different prognosis and survival time. This example demonstrates that molecular biological analysis allows a better estimation of the individual risk in patients with a monogenetic disease. Such diseases are an important target for genetic therapies, as transfection of normal copies of the diseased gene would potentially cure the patient. Clinical experience has so far only been obtained in patients with familial hypercholesterolaemia and mutations in the LDL receptor. Molecular biology also permits a better understanding of the pathogenesis of atherosclerosis, which is responsible for most cardiovascular disease. Atherosclerosis is a disease of conduit arteries such as the aorta and the coronary arteries. In recent years it has become possible to characterise better the molecular and cellular changes leading to endothelial dysfunction, coronary vasospasm, adhesion of monocytes and lymphocytes, proliferation and migration of vascular smooth muscle cells, and formation of extracellular matrix. This improved understanding has led to new therapeutic approaches, although a genetic intervention is not probable for the moment due to the complexity of the disease process. Balloon dilatation of coronary arteries has generated a new disease, namely restenosis. Vascular remodelling and proliferation are of major importance for this disease. Many cellular mechanisms have been characterised, and gene therapeutic strategies including signal transduction and cell cycle regulation have already been investigated experimentally. Coronary bypass graft disease represents another target for gene therapy in the vascular system. Many experimental and a few clinical protocols have been performed with the saphenous vein. Yet another strategy for gene therapy is the endogenous formation of new vessels due to the effect of vascular endothelial growth factor. Molecular cardiology is a new and promising approach to a better understanding of cardiovascular disease. Genetic analysis is already established for the diagnosis of single gene disorders and, in addition, allows a more precise prognostic evaluation. Cardiovascular gene therapy has been focussing mainly on angiogenesis; other strategies, however, are under investigation mainly in an experimental setting.

Overexpression of connective tissue growth factor gene induces apoptosis in human aortic smooth muscle cells

BACKGROUND

Connective tissue growth factor (CTGF) is expressed at very high levels particularly in the shoulder of human atherosclerotic lesions but not in normal blood vessels. Thus, CTGF may be important in the regulation of vascular smooth muscle cell function in atherosclerosis, but its precise role remains elusive.

METHODS AND RESULTS

Full-length CTGF cDNA driven by a cytomegalovirus promoter was transiently transfected into cultured human aortic smooth muscle cells (HASCs). Northern and Western analysis demonstrated that CTGF was overexpressed in these cells 48 hours after transfection. The effects of CTGF overexpression on cell proliferation were evaluated by [(3)H]thymidine uptake and cell count in quiescent HASCs or those stimulated with platelet-derived growth factor (PDGF). Although mock transfection showed no effect, CTGF overexpression significantly inhibited cell proliferation in cells stimulated by PDGF. Moreover, CTGF overexpression, but not mock transfection, significantly increased apoptosis as assessed by DNA fragmentation associated with histone, TdT-mediated dUTP biotin nick end-labeling, and appearance of hypodiploid cells by flow cytometry.

CONCLUSIONS

Our results for the first time demonstrate that CTGF can also act as a growth inhibitor in human aortic smooth muscle cells at least in part by inducing apoptosis. This may be important for the formation and composition of lesions and plaque stability in atherosclerosis.

Expression of cyclin-dependent kinase inhibitors in vascular disease

Arterial lesions in cardiovascular diseases are characterized by proliferation and migration of smooth muscle cells as well as deposition of connective tissue matrix. Factors that stimulate vascular smooth muscle cell (VSMC) proliferation are well described; however, the role of proteins that limit intimal hyperplasia is not well understood. To examine the function of Kip/Cip and INK cyclin-dependent kinase inhibitors (CKIs) in vascular diseases, the expression of p27Kip1 and p16INK was examined in VSMCs in vitro and in porcine arteries and human atherosclerosis in vivo. Western blot and fluorescence activated cell-sorting analysis demonstrated that levels of p27Kip1, but not p16INK, increased during serum deprivation of primary VSMC cultures and caused G1 arrest. p27Kip1 inhibited Cdk2 activity, suggesting that Kip CKIs promote G1 arrest in VSMCs by binding cyclin E/Cdk2. In porcine arteries, p27Kip1, but not p16INK, was constitutively expressed at low levels. Immediately after balloon injury, cell proliferation increased as p27Kip1 levels declined. Three weeks after injury, p27Kip1 was strongly expressed in intimal VSMCs when VSMC proliferation was < 2%, suggesting that p27Kip1 functions as an inhibitor of cell proliferation in injured arteries. In contrast, p16INK expression was detected only transiently early after injury. CKI expression was examined in 35 human coronary arteries, ranging from normal to advanced atherosclerosis. p27Kip1 expression was abundant in nonproliferating VSMCs and macrophages within normal (7 of 8) and atherosclerotic (25 of 27) arteries. p21Cip1 levels were undetectable in normal arteries but were elevated in atherosclerotic (19 of 27) arteries. p16INK could not be detected in normal or atherosclerotic arteries (0 of 35). Thus, the Kip/Cip and INK CKIs have different temporal patterns of expression in VSMCs in vitro and in injured arteries and atherosclerotic lesions in vivo. In contrast to p16INK, p27Kip1 likely contributes to the remodeling process in vascular diseases by the arrest of VSMCs in the G1 phase of the cell cycle.

Transfection of human endothelial cells

OBJECTIVE

The introduction of recombinant genes into endothelial cells provides a method to study specific gene products and their effect on cell function. In addition, endothelial cells can be used for implantation into vessels or prosthetic vascular grafts. Because transfection efficiencies in human endothelial cells have been low, it is important to develop improved gene transfer techniques. Therefore, several transfection methods were optimized and transfection efficiencies were determined.

METHODS

Transfection by particle-mediated gene transfer (biolistics) or by cationic liposomes were optimized and compared to calcium phosphate and DEAE-dextran. Transfection efficiency was determined using either a beta-galactosidase or placental alkaline phosphatase reporter gene. The effect of promoter strength was analyzed by transfecting plasmids with either the Rous sarcoma virus (RSV) promoter or cytomegalovirus (CMV) promoter regions.

RESULTS

Optimal conditions for particle-mediated gene transfer utilized gold particles of 1.6 microns diameter, a target distance of 3 cm, helium pressures of 8.96 MPa (1300 psi) and cell confluence of 75%. Transfection with different cationic liposomes demonstrated that one compound, N-(3-aminopropyl)-N,N-dimethyl-2,3-(bis-dodecyloxy)-1-propanimi nium bromide/dioleoyl phosphatidylethanolamine (gamma AP-DLRIE/DOPE), was optimal for gene transfer when 5 micrograms of DNA and 10 to 20 micrograms of lipid was used. With both gold particles and gamma AP-DLRIE/DOPE, the alkaline phosphatase reporter was more efficient than beta-galactosidase using comparable promoters and polyadenylation sites. CMV regulatory elements were more efficient than the RSV promoter in optimizing gene expression. Optimal gene transfer efficiency was 20.28% of cells with gamma AP-DLRIE/DOPE, 3.96% with biolistics, 2.09% with calcium phosphate and 0.88% with DEAE-dextran.

CONCLUSIONS

Gene expression is detectable in a high percentage of human endothelial cells after liposome-mediated transfection when expression is controlled by a strong promoter. Particle-mediated transfection is less efficient under these conditions, but more effective than liposomes when expression is driven by a relatively weak promoter. Calcium phosphate and DEAE-dextran are less useful.

In vivo gene delivery to the pulmonary circulation in rats: transgene distribution and vascular inflammatory response

Although gene delivery to the pulmonary circulation has both experimental and therapeutic potential, the delivery methods, distribution of transgene, and subsequent inflammatory response have been poorly characterized to date. To address these issues, we utilized a 0.76-mm OD (outside diameter) end hole catheter inserted into the internal jugular vein of adult Sprague-Dawley rats, directing the tip into a pulmonary capillary wedge position. We then compared infusion of polycationic lipid:DNA complexes to replication-defective adenovirus with respect to magnitude and distribution of transgene expression using either chloramphenicol acetyltransferase (CAT) or human placental alkaline phosphatase (hpAP) reporter genes. Both lipid:DNA and adenovirus resulted in detectable transgene expression, though maximum lung CAT activity using lipid (gamma AP-DLRIE/DOPE) was approximately 2% of maximum activity using adenovirus (Ad-CAT). Further characterization of expression after transfection with 10(8) pfu (plaque forming units) of Ad-CAT demonstrated persistence of transgene for at least 14 days (lung CAT activity 27% of maximum). Alkaline phosphatase staining demonstrated that both large and small pulmonary arteries as well as the alveolar wall expressed transgene. Although little inflammatory response was detected in conduit arteries, a predominantly mononuclear cell infiltrate surrounded small pulmonary arteries as well as the alveolar spaces in transfected areas of lung. We conclude that percutaneous catheter-mediated gene delivery to the pulmonary circulation in rats using non-viral and viral vectors is feasible. Although an inflammatory response to first generation replication-defective adenovirus was detected, it appeared to be largely restricted to the distal pulmonary circulation and airspace. This technique should prove useful for investigations requiring overexpression of novel genes in the pulmonary artery wall, and could ultimately be used to develop gene-based therapies for pulmonary vascular diseases.

Gene transfer approaches to the regulation of vascular cell proliferation

Considerable progress has been made in identifying potential targets for treating vascular proliferative diseases. In this review, we discuss gene transfer approaches to regulating smooth muscle cell proliferation after vascular injury using the cell cycle specific proteins, p21, delta Rb and HSV-tk. Results from these studies suggest that replicating smooth muscle cells and macrophages are inhibited in vivo in several animal models of restenosis, including hyperlipidaemic vessels. Identification of appropriate vascular diseases and improvements in gene delivery and vectors will require careful optimization in order to develop effective molecular therapies for human vascular diseases.

Lipids and endothelial function: effects of lipid-lowering and other therapeutic interventions

Coronary arteries are regulated by neuronal mechanisms, hormones and paracrine mediators. The importance of endothelium-dependent mechanisms has recently been recognized. The endothelium responds to mechanical and chemical signals from the blood by releasing mediators that modulate vascular tone and structure, platelet function, coagulation and monocyte adhesion. Important relaxing factors are nitric oxide, prostacyclin and a putative hyperpolarizing factor. Nitric oxide also inhibits smooth muscle proliferation and, together with prostacyclin, platelet function. Bradykinin-induced nitric oxide production is reduced by angiotensin-converting enzyme. Endothelin-1, thromboxane A2 and prostaglandin H2 are contracting factors. Thromboxane A2 and prostaglandin H2 activate platelets, while endothelin has no direct platelet effects, but causes smooth muscle proliferation. In hypercholestermia, endothelium-dependent relaxation is impaired and contraction as well as adhesion of monocytes and platelets enhanced. Pharmacological correction of hyperlipidemia by statins also improves or normalizes endothelial dysfunction in patients. Angiotensin-converting enzyme inhibitors have similar effects.

Endothelial regulation of vascular tone and growth

The endothelium regulates vascular tone by releasing factors involved in relaxation and contraction, in coagulation and thrombus formation, and in growth inhibition and stimulation. Endothelium-dependent relaxations are elicited by transmitters, hormones, platelet substances, and the coagulation system, and by physical stimuli such as the shear stress from circulating blood. They are mediated by the endothelium-derived relaxing factor, recently identified as nitric oxide, which causes vasodilation and platelet deactivation. Other proposed endothelium-derived relaxing factors include a hyperpolarizing factor, lipooxygenase products, and the cytochrome P450 pathway. Endothelium-derived contracting factors are produced by the cyclooxygenase pathway and by endothelial cells, which produce the peptide endothelin-1, a potent vasoconstrictor that under normal conditions circulates at low levels. The endothelium produces both growth inhibitors--normally dominant--and growth stimuli. Denuded or dysfunctional endothelium leads to a proliferative response and intimal hyperplasia in the vessel wall; moreover, platelets adhere to the site and release potent growth factors. Endothelial dysfunction has numerous causes: Aging is associated with increased formation of contracting factor and decreased relaxing factor; denudation, such as by coronary angioplasty, impairs the capacities of regenerated endothelial cells; oxidized low-density lipoproteins and hypercholesterolemia interfere with nitric oxide production; hypertension morphologically and functionally alters the endothelium; and atherosclerosis markedly attenuates some endothelium-dependent relaxations. For patients with coronary bypass grafts, differences in endothelium-derived vasoactive factors between the internal mammary artery and the saphenous vein may be important determinants of graft function, with the mammary artery having more pronounced relaxations than the saphenous vein and thus a higher patency rate.

Endothelium-derived nitric oxide, endothelin, and platelet vessel wall interaction: alterations in hypercholesterolemia and atherosclerosis

The endothelium modulates vascular tone by releasing NO, which is a potent vasodilator and inhibitor of platelet aggregation. Thus, the endogenous nitrate has an important protective role in preventing vasospasm and thrombus formation. In addition, the endothelium is a source of contracting factors, such as endothelin-1. Due to its strategical anatomic position, the endothelium is a primary target for injurious stimuli and cardiovascular risk factors. Oxidized LDL reduce the endothelial production of NO and enhance that of endothelin-1. The same pattern of endothelial dysfunction occurs in hypercholesterolemia and in part in atherosclerosis. These alterations of endothelial function may contribute to vasospasm and thrombus formation, which are common events in patients with atherosclerosis.

Endothelial dysfunction in coronary artery disease

The endothelium is a physical barrier between the blood and vascular smooth muscle, a source of enzymes activating and deactivating cardiovascular hormones and a site of production of relaxing and contracting factors. In addition, the endothelium is a source of growth inhibitors and promoters of vascular smooth muscle cells. Monoaminooxidase deactivates catecholamines and serotonin. Angiotensin converting enzyme transforms angiotensin I into angiotensin II and breaks down bradykinin into inactive products. Nitric oxide is a potent vasodilator and inhibitor of platelet function that under most circumstances is released together with prostacyclin, which exerts similar effects. Both substances play an important protective role in the coronary circulation in that they cause continuous vasodilation and inhibition of platelet function. In addition, the endothelium is a source of contracting factors such as endothelin-1, thromboxane A2, and endoperoxides. Endothelium-derived growth inhibitors include heparin (sulfates) and transforming growth factor beta 1, while basic fibroblast growth factors and platelet-derived growth factor and possibly endothelin promote proliferation. Because of its strategic anatomic position, the endothelium is a primary target for injuries and cardiovascular risk factors. In particular, aging, low density lipoproteins, hypertension, diabetes, and ischemia alter endothelium function. In arterial coronary bypass grafts, the release of nitric oxide is more pronounced than in vein grafts. Alterations of endothelial function may contribute to vasospasm, thrombus formation, and vascular proliferation and in turn myocardial ischemia, all common events in patients with coronary artery disease.

Oxidized low density lipoproteins induce mRNA expression and release of endothelin from human and porcine endothelium

Experiments were designed to examine the effect of oxidized low density lipoproteins (Ox-LDLs) on the expression and the release of endothelin from cultured endothelial cells and intact blood vessels. Ox-LDLs (30-300 micrograms/ml), but not native low density lipoproteins (200 micrograms/ml), stimulated the expression of preproendothelin mRNA in porcine and human endothelial cells, leading to a time- and concentration-dependent release of the peptide into the culture medium. The Ox-LDL-stimulated release of endothelin was mimicked by acetylated low density lipoprotein and abolished by downregulation of protein kinase C by phorbol ester. In the intact porcine aorta, Ox-LDLs, but not native low density lipoproteins, also increased the release of peptide in an endothelium- and concentration-dependent manner. The maximal effect was observed at a concentration of 100 micrograms/ml. Incubation of the intact porcine aorta with the scavenger receptor antagonist dextran sulfate decreased the formation of endothelium evoked by Ox-LDLs. The Ox-LDL-stimulated production of the peptide was further augmented in the presence of thrombin (4 units/ml) and was unaffected by nitric oxide-generating compound 3-morpholinosydnonimine (10(-5) M). These results suggest that Ox-LDL may be an endogenous mediator of the augmented release of endothelin observed in hyperlipidemia and atherosclerosis. The increased production of the peptide could contribute to vasospastic events and may promote vascular smooth muscle proliferation and progression of atherosclerotic vascular disease.

Age, hypertension and hypercholesterolaemia alter endothelium-dependent vascular regulation

As a source of several vasoactive factors, the endothelium takes part in the regulation of vascular tone. The most important endothelium-derived vasoactive substances are nitric oxide, prostacyclin, endothelin-1 and contracting factors requiring the activity of cyclooxygenase. The endothelium is an obvious target organ of cardiovascular risk factors. Accordingly, functional alterations do occur with aging, hypertension and hypercholesterolaemia. All three conditions are associated with a decreased basal and simulated release of endothelium-derived nitric oxide. On the other hand, the release of endothelin-1 appears to increase with age, while the sensitivity to the peptide markedly decreases under the same conditions. In the spontaneously hypertensive rat, acetylcholine and stretch evoke the release of a cyclooxygenase-dependent endothelium-derived contracting factor, most likely prostaglandin H2. The circulating levels of endothelin-1 on the other hand are not increased in experimental and human hypertension. In the porcine coronary circulation, oxidized low-density lipoproteins selectively reduced endothelium-dependent relaxations to aggregating platelets, serotonin and thrombin which are mediated by nitric oxide. The alterations of endothelial function occurring with aging, hypertension and hypercholesterolaemia may have important clinical implications for the pathogenesis of cardiovascular disease.

Oxidized low density lipoproteins inhibit relaxations of porcine coronary arteries. Role of scavenger receptor and endothelium-derived nitric oxide

BACKGROUND

We studied the effects of low density lipoprotein (LDL) on endothelium function.

METHODS AND RESULTS

Porcine epicardial and intramyocardial coronary arteries suspended in organ chambers for isometric tension recording were exposed to LDL for 2 hours and were then washed. In epicardial coronary arteries, oxidized LDL (30-300 micrograms/ml) but not native LDL or lysolecithin inhibited endothelium-dependent relaxations to serotonin, thrombin, and aggregating platelets (5,000-75,000/microliter). Endothelium-dependent relaxations to bradykinin and A23187 and endothelium-independent relaxations to SIN-1 were unaffected by oxidized LDL. In intramyocardial coronary arteries, oxidized LDL had no appreciable effect on relaxations to serotonin. The effect of oxidized LDL on the response to serotonin in epicardial coronary arteries was completely prevented by dextran sulfate (10 micrograms/ml). The inhibitory effect of oxidized LDL persisted in the presence of pertussis toxin. Similar to the lipoproteins, L-NG-monomethyl arginine (L-NMMA) reduced relaxations to serotonin but not to bradykinin in epicardial coronary arteries. In the presence of L-NMMA, oxidized LDL further reduced the response to serotonin. In arteries in which relaxations to serotonin were inhibited by oxidized LDL, L-arginine but not D-arginine induced a full relaxation. Pretreatment with L-arginine potentiated relaxations to serotonin in arteries exposed to oxidized LDL.

CONCLUSIONS

Thus, oxidized LDL activates the scavenger receptor on endothelial cells and inhibits the receptor-operated nitric oxide formation in epicardial but not in intramyocardial coronary arteries. The mechanism is not related to dysfunction of a Gi protein but is related to a reduced intracellular availability of L-arginine. The reduced nitric oxide formation at sites of early atherosclerotic lesions may favor platelet aggregation and vasospasm, both of which are known clinical events in patients with coronary artery disease.

Endothelium-dependent control of vascular tone: effects of age, hypertension and lipids

As a source of several vasoactive factors, the endothelium takes part in the regulation of vascular tone. The most important endothelium-derived vasoactive substances are nitric oxide, prostacyclin, endothelin-1 and contracting factors requiring the activity of cyclooxygenase. The endothelium is an obvious target organ of cardiovascular risk factors. Accordingly, functional alterations do occur with aging, hypertension, and lipids. All three conditions are associated with a decreased basal and stimulated release of endothelium-derived nitric oxide. On the other hand, the release of endothelin-1 appears to increase with age, while the sensitivity to the peptide markedly decreases under the same conditions. In the spontaneously hypertensive rat, acetylcholine and stretch evoke the release of cyclooxygenase-dependent endothelium-derived contracting factor, most likely prostaglandin H2. The sensitivity and circulating levels of endothelin-1, on the other hand, are reduced in this experimental model of hypertension. In the porcine coronary circulation, oxidized low-density lipoproteins selectively reduce endothelium-dependent relaxations to aggregating platelets, serotonin, and thrombin which are mediated by nitric oxide. The alterations of endothelial function occurring with aging, hypertension, and hyperlipidemia may have important clinical implications for the pathogenesis of cardiovascular disease.

Different activation of L-arginine pathway by bradykinin, serotonin, and clonidine in coronary arteries

Endothelial cells release nitric oxide from L-arginine, and this pathway can be inhibited by the analogue of L-arginine, NG-monomethyl-L-arginine (L-NMMA). The effect of L-NMMA on endothelium-dependent relaxation of epicardial porcine coronary arteries was studied in isolated blood vessels suspended in organ chambers for isometric tension recording. Endothelium-dependent relaxations to bradykinin, serotonin, and the alpha 2-adrenergic agonist clonidine were evaluated in the presence and absence of L-NMMA (10(-5)-10(-3) M). L-NMMA, as well as the inhibitor of guanylate cyclase methylene blue (10(-5) M) and hemoglobin (10(-5) M), inhibited endothelium-dependent relaxation to serotonin and clonidine. The effect of L-NMMA could be reversed by L-arginine but not by D-arginine. In contrast, L-NMMA, methylene blue, and hemoglobin caused a weak inhibition of the endothelium-dependent relaxation evoked by bradykinin; indomethacin and tranylcypromine had no effect. The inhibitor of Gi proteins pertussis toxin (100 ng/ml) abolished the relaxations evoked by clonidine and markedly reduced those evoked by serotonin but did not affect those caused by bradykinin. In the presence of pertussis toxin, L-NMMA induced a further reduction of the relaxations to serotonin, suggesting that inhibition of Gi proteins does not completely prevent the activation of the L-arginine pathway. Thus endothelium-dependent relaxations to serotonin and to the alpha 2-adrenergic agonist clonidine are mediated through the release of nitric oxide formed from L-arginine in endothelial cells, whereas bradykinin evokes endothelium-dependent relaxations via a different pathway.

[Epidemic listeriosis. Report of 25 cases in 15 months at the Vaud University Hospital Center]

25 cases (14 adults, 11 neonates) of Listeria monocytogenes infection were observed during a 15-month period (1983/1984) at the University Medical Center (CHUV) in Lausanne (Switzerland), in contrast to a mean of only 3 cases per year during the period 1974-1982. Eleven of 14 adults had neuromeningeal disease (3 meningitis, 7 meningoencephalitis, 1 encephalitis), and 3 patients had septicemia, two of whom were pregnant women. Among 8 adults with CNS parenchymal infection, 6 had involvement of the brainstem (rhombencephalitis), none of whom had an underlying disease characteristically predisposing to L. monocytogenes infection. Prominent clinical features in all patients with neuromeningeal disease included altered consciousness, headache and fever, and in 7 out of 8 patients with parenchymal CNS involvement an influenza-like illness was present prior to the development of neurological symptoms. Among the neuromeningeal cases the mortality rate was 45% (5 of 11), and 4 out of 6 survivors had severe neurological sequelae. During this 15-month period L. monocytogenes had become the leading cause of adult bacterial meningitis in this hospital. This is the first report on epidemic listeriosis in Switzerland, although sporadic cases have been described for 20 years. In contrast to previous years, analysis of the seasonal variation of the cases shows a peak of L. monocytogenes infections during the winter months of 1983/84. The high incidence of human listeriosis was not associated with an increase in animal cases. The human cases were uniformly distributed over the area, apparently in relation to population density.(ABSTRACT TRUNCATED AT 250 WORDS)