Importance of contractile reserve for CRT

AIMS

To assess whether response to cardiac resynchronization therapy (CRT) is related to myocardial viability in the paced left ventricular (LV) region, evaluated by contractile reserve (CR). Non-response to CRT may partly be due to inefficient pacing by the LV lead located in a fibrotic area.

METHODS AND RESULTS

Nineteen patients (64 +/- 13 years, 14 men, 9 ischaemic) with severe heart failure (EF = 27 +/- 8%, QRS = 154 +/- 25 ms) were included in the week after device implantation. Stroke volume (SV) and LV dyssynchrony (by Tissue Doppler Imaging) were successively assessed with CRT on and CRT off. Afterwards, CRT device was maintained off during dobutamine infusion to assess CR in the LV-pacing region. LV end-systolic volume (ESV) was assessed after 6 months to quantify reverse remodelling. CR in the paced LV region (n = 10, 5/9 ischaemic and 5/10 non-ischaemic) was correlated to a reduction in LV dyssynchrony under CRT (120 +/- 76 vs. 78 +/- 64 ms, P = 0.02). Conversely, LV dyssynchrony was unchanged (161 +/- 100 vs. 163 +/- 80 ms) without CR. In desynchronized patients (>65 ms, n = 15), increase in SV under CRT and changes in ESV at 6 months were +22 and -18%, respectively, when CR was present and 0% and +9%, respectively, when absent.

CONCLUSION

Acute haemodynamic response and reverse remodelling under CRT require viability in the target region of LV lead.

Bypassing the emergency room reduces delays and mortality in ST elevation myocardial infarction: the USIC 2000 registry

OBJECTIVE

To study the impact on outcomes of direct admission versus emergency room (ER) admission in patients with ST-segment elevation myocardial infarction (STEMI) DESIGN: Nationwide observational registry of STEMI patients

SETTING

369 intensive care units in France.

INTERVENTIONS

Patients were categorised on the basis of the initial management pathway (direct transfer to the coronary care unit or catheterisation laboratory versus transfer via the ER).

MAIN OUTCOME MEASURES

Delays between symptom onset, admission and reperfusion therapy. Mortality at five days and one year.

RESULTS

Of 1204 patients enrolled, 66.9% were admitted direct and 33.1% via the ER. Bypassing the ER was associated with more frequent use of reperfusion (61.7% v 53.1%; p = 0.001) and shorter delays between symptom onset and admission (244 (interquartile range 158) v 292 (172) min; p < 0.001), thrombolysis (204 (150) v 258 (240) min; p < 0.01), hospital thrombolysis (228 (156) v 256 (227) min, p = 0.22), and primary percutaneous coronary intervention (294 (246) v 402 (312) min; p < 0.005). Five day mortality rates were lower in patients who bypassed the ER (4.9% v 8.6%; p = 0.01), regardless of the use and type of reperfusion therapy. After adjusting for the simplified Thrombolysis in Myocardial Infarction (TIMI) risk score, admission via the ER was an independent predictor of five day mortality (odds ratio 1.67, 95% confidence interval 1.01 to 2.75).

CONCLUSIONS

In this observational analysis, bypassing the ER was associated with more frequent and earlier use of reperfusion therapy, and with an apparent survival benefit compared with admission via the ER.

High risk hypertensives: pre-hospital management of acute myocardial infarction--results from the French nationwide registry USIC 2000

OBJECTIVE

To assess the use of mobile coronary care units (MCU) in hypertensive patients previously treated for cardiovascular diseases in comparison with those with no history of cardiovascular disease and to estimate the influence of the use of MCU on cardiovascular outcome in this population.

PATIENTS

We used a nationwide prospective registry of all patients admitted for AMI in French intensive care units in 2000. Patients without history of hypertension or patients admitted with pulmonary oedema or cardiogenic shock were excluded. Men (N = 514) and women (N = 291) were analysed separately.

RESULTS

The proportion of patients with history of myocardial infarction, peripheral artery disease and stroke was not significantly higher in subjects who used physician-staffed MCU as compared with patients with no history of myocardial infarction, peripheral artery disease or stroke. In each sex, revascularization (pre hospital fibrinolysis, in hospital fibrinolysis or coronary angioplasty) were more frequent in patients who used MCU. Also, one year cardiovascular mortality was lower in men who used MCU.

CONCLUSION

Known high risk hypertensive patients did not use physician-staffed MCU more than subjects free of such condition. Education of hypertensive patients at risk during routine visits is required to increase of the use of physician-staffed MCU in case of symptoms suggestive of AMI.

Impact of age and gender on in-hospital and late mortality after acute myocardial infarction: increased early risk in younger women: results from the French nation-wide USIC registries

AIMS

To determine whether sex differences of in-hospital and after-discharge mortality differ according to the age.

METHODS AND RESULTS

Data of 4347 consecutive patients hospitalized within 48 h of the onset of acute myocardial infarction (AMI) were analysed. Patients were classified according to median age (68 years): Group 1 (G1) (308 women, 30-67 years), G2 (1878 men, 30-67 years), G3 (860 women, 68-89 years), and G4 (1301 men, 68-89 years). In both age groups, women were older, had more frequent co-morbidities, lower rate of reperfusion therapy, and received less anti-platelet agents, beta-blockers, and statins than men. The overall 1-year mortality was higher in women (25% vs. 16% in men, P<0.0001). After adjustment, in-hospital mortality was higher only for the women in the younger age group. (G1 vs. G2: OR=2.2, 95%CI=1.3-3.8; G3 vs. G4: OR=1.1, 95%CI=the risk of death, after hospital discharge, was no longer related to gender in any age group.

CONCLUSION

The higher 1-year mortality following AMI in women is explained by the higher risk of death in young women during the first days of hospitalization. Further investigations are crucial to determine the cause in order to improve the chance of survival in younger women.

Major impact of admission glycaemia on 30 day and one year mortality in non-diabetic patients admitted for myocardial infarction: results from the nationwide French USIC 2000 study

OBJECTIVE

To analyse the short and long term prognostic significance of admission glycaemia in a large registry of non-diabetic patients with acute myocardial infarction.

METHODS

Assessment of short and long term prognostic significance of admission blood glucose in a consecutive population of 1604 non-diabetic patients admitted to intensive care units in France in November 2000 for a recent (<or= 48 hours) myocardial infarction.

RESULTS

In-hospital mortality, compared with that of patients with admission glycaemia below the median value of 6.88 mmol/l (3.7%), rose gradually with each of the three upper sextiles of glycaemia: 6.5%, 12.5% and 15.2%. Conversely, one year survival decreased from 92.5% to 88%, 83% and 75% (p < 0.001). Admission glycaemia remained an independent predictor of in-hospital and one year mortality after multivariate analyses accounting for potential confounders. Increased admission glycaemia also was a predictor of poor outcome in all clinical subsets studied: patients without heart failure on admission, younger and older patients, patients with or without reperfusion therapy, and patients with or without ST segment elevation.

CONCLUSION

In non-diabetic patients, raised admission blood glucose is a strong and independent predictor of both in-hospital and long term mortality.

[Combination therapy at hospital discharge in the USIC 2000 survey]

We tried to determine the prognostic impact of triple (antiplatelet agents, statins and beta-blockers) and quadruple (the same+ACE inhibitors) combination therapy at hospital discharge after acute myocardial infarction. The USIC 2000 survey is nationwide registry of consecutive patients admitted to intensive care units for acute myocardial infarction in November 2000 in France. Of the 2119 patients discharged alive, 1095 (52%) were prescribed a combination of antiplatelet agents, beta-blockers and statins (triple therapy), including 567 (27%) with a similar combination plus ACE inhibitors (quadruple therapy). One-year survival was 97% in patients receiving triple combination therapy versus 88% in those who received either no, one or two of these medications (p < 0.0001). After multivariate adjustment, the odds ratio for one-year mortality in patients with triple combination therapy was 0.49 (95% confidence interval: 0.32-0.75). Quadruple combination therapy had no additional predictive value in the entire population. In patients with ejection fraction < or = 35%, however, beta-blockers and ACE inhibitors were independent predictors of survival, and combination therapy had no additional prognostic value.

CONCLUSIONS

compared with the prescription of any single class of secondary prevention medications, combination therapy offers additional protection in patients with acute myocardial infarction.

Impact of combined secondary prevention therapy after myocardial infarction: data from a nationwide French registry

BACKGROUND

Several classes of medications improve survival in patients with coronary artery disease. Whether these medications, as used in the real world, have additive efficacy remains speculative.

OBJECTIVES

To assess whether patients discharged on combined secondary prevention medications after acute myocardial infarction (AMI) have improved 1-year survival, compared with the action of any single class of medications.

DESIGN AND SETTING

Nationwide registry of consecutive patients admitted to intensive care units for AMI in November 2000 in France. Multivariate Cox regression analysis, including a propensity score for the prescription of combined therapy, was used.

RESULTS

Of the 2119 patients discharged alive, 1095 (52%) were prescribed a combination of antiplatelet agents, beta-blockers, and statins (triple therapy), of whom 567 (27%) also received angiotensin-converting enzyme inhibitors (quadruple therapy) and 528 (25%) did not. One-year survival was 97% in patients receiving triple combination therapy versus 88% in those who received either none, 1, or 2 of these medications (P < .0001). After multivariate adjustment including the propensity score, the hazard ratio for 1-year mortality in patients with triple combination therapy was 0.52 (95% CI 0.33-0.81). In patients with ejection fraction < or = 35%, beta-blockers and angiotensin-converting enzyme inhibitors were independent predictors of survival, and combination therapy had no additional prognostic value.

CONCLUSIONS

Compared with the prescription of any single class of secondary prevention medications, combination therapy offers additional protection in patients with AMI.

[Echocardiography and mechanical complications of recent myocardial infarction]

The constantly advancing technology of echocardiography and its widespread usage in the intensive care unit has made it a routine examination in patients with acute myocardial infarction. It has become the reference method for diagnosis and monitoring of certain complications such as pericardial effusion, intra-ventricular thrombosis, ventricular aneurysm and mitral regurgitation. The echocardiographic description of these complications dates back to the 1980s during which prospective studies accurately described the principal abnormalities. These descriptions have not been much improved upon with the advent of new technology. On the other hand, the frequency of these complications assessed in an era when reperfusion by thrombolysis or primary angioplasty was much less common than today, has considerably decreased.

[Management of patients admitted for acute myocardial infarction in France from 1995 to 2000: time to admission dependent improvement in outcome]

The in-hospital management and short- and long-term outcomes was assessed in 2 registries of consecutive patients admitted for acute myocardial infarction, 5 years apart, in France. The 2000 cohort was younger and with a less frequent history of cardiac diseases, but was more often diabetic and with anterior infarcts. Time to admission was actually longer in 2000 than in 1995 (median 5.25 hours vs 4.00 hours). Overall, reperfusion therapy was used in 43% of the patients in both registries. However, the use of reperfusion therapy increased from 1995 to 2000 in patients admitted within 6 hours of symptom onset (64 vs 58%), with an increasing use of primary angioplasty (from 12 to 30%). Five-day mortality significantly improved from 7.7 to 6.1% (p < 0.03) and one-year survival was also less in the most recent period (85 vs 81%, p < 0.01). Multivariate analyses showed that the period of inclusion (2000 vs 1995) was an independent predictor of both short- and long-term mortality in patients admitted within 6 hours of symptom onset. Thus, in the real world setting, a continued decline in one-year mortality was observed in patients admitted to intensive care units for recent acute myocardial infarction, especially for patients admitted early. This goes along with a shift in reperfusion therapy towards a broader use of primary angioplasty, and with an increased use of the early prescription of recognised secondary prevention medications.

Perindopril/indapamide combination more effective than enalapril in reducing blood pressure and left ventricular mass: the PICXEL study

OBJECTIVE

Few data are available comparing the effects of monotherapy and combination therapy on target organ damage. The PICXEL study compared the efficacy of a strategy based on first-line combination with perindopril/indapamide versus monotherapy with enalapril in reducing left ventricular hypertrophy (LVH) in hypertensive patients.

METHODS

In this 1-year multicentre randomized double-blind study, patients received an increasing dosage of perindopril/indapamide (n = 284) or enalapril (n = 272). Changes in blood pressure and echocardiographic measures of LVH were assessed from baseline to the end of treatment. Reading of the echocardiograms was central and blinded for therapy, patient and sequence.

RESULTS

Systolic and diastolic blood pressure decreased significantly more in the perindopril/indapamide than in the enalapril group (P < 0.0001 and P = 0.003). The left ventricular mass index decreased by 13.6 +/- 23.9 g/m(2) (mean +/- SD) with perindopril/indapamide (P < 0.0001) and 3.9 +/- 23.9 g/m(2) with enalapril (P < 0.005); these decreases were significantly different (P < 0.0001). The left ventricular internal diameter, posterior and interventricular septal wall thickness decreased significantly with perindopril/indapamide (P < or = 0.0001); the interventricular septal wall thickness decreased significantly with enalapril (P < 0.001). Both treatments were well tolerated.

CONCLUSION

A strategy based on first-line combination with perindopril/indapamide achieved better blood pressure decrease with a significantly greater degree of LVH reduction than a strategy based on monotherapy with enalapril in hypertensive patients with LVH.

[Clinical and therapeutic specificities of myocardial infarction in patients with peripheral arterial disease: the USIC 2000 registry]

OBJECTIVE

Several studies underlined the worse prognosis of myocardial infarction (MI) among patients with peripheral arterial disease (PAD). We sought to describe the presentation and management modalities of a cohort of PAD patients presenting an acute MI, compared to those without PAD.

MATERIALS AND METHODS

The USIC 2000 registry, a nationwide database on all patients admitted to a CCU for an acute MI < 48 hours in France in November 2000 was used for this study.

RESULTS

Among the 2311 patients included, PAD was reported in 215 subjects (9.3%). In multivariate analysis, the following factors were positively related to the presence of PAD (P < or = 0.05): age >75 y (OR = 2.3), diabetes (OR = 2.0), hypertension (OR = 1.4), active smoking (OR = 4.6), renal failure (OR =3.1), and treatments with antiplatelets (OR = 3.9), anti-vitamin K (OR = 1.9), statins (OR = 1.7) and low molecular weight heparins (OR = 6.8). By introducing the data concerning the arrival in CCUs in the model, the following factors were also significantly more frequent among PAD patients: male sex (OR = 1.6), past history of coronary artery disease (OR = 2.2), left bundle branch block (OR = 1.8) and late management >6 hours (OR = 1.4). Conversely, ST-segment elevation was less frequent (OR = 0.7). When the CCU stay data were introduced in the model, a lower rate of coronary stenting (OR = 0.7) and betablockers use within 48 hours of admission (OR = 0.6) were noted.

CONCLUSION

Beyond the presence of PAD per se, several particularities do exist, especially the coexistence of a high number of pejorative factors and an under-utilization of treatments presenting prognostic benefits.

Usefulness of plasma B-type natriuretic peptide in predicting recurrence of atrial fibrillation one year after external cardioversion

After successful external cardioversion, the rate of recurrence of atrial fibrillation remains high. The hypothesis that plasma B-type natriuretic peptide could predict the recurrence of atrial fibrillation at 1 year was tested. Plasma B-type natriuretic peptide was measured in 66 consecutive asymptomatic patients who underwent external cardioversion for atrial fibrillation. Twelve-lead electrocardiograms were obtained at 1 year. Sinus rhythm was maintained in 55% of patients. The independent predictors of the recurrence of atrial fibrillation at 1 year were a history of atrial fibrillation, plasma B-type natriuretic peptide, and the energy delivered for conversion. In patients without symptoms of heart failure, plasma B-type natriuretic peptide is an independent predictor of the recurrence of atrial fibrillation.

Role of previous treatment with sulfonylureas in diabetic patients with acute myocardial infarction: results from a nationwide French registry

BACKGROUND

The cardiovascular effects of sulfonylureas (SU) in diabetic patients are controversial and it has been suggested that diabetic patients with acute myocardial infarction while on SU were at increased risk.

OBJECTIVES

To assess the in-hospital outcome of patients with acute myocardial infarction according to the use of SU at the time of the acute episode.

METHODS

Of 443 intensive care units in France, 369 (83%) prospectively collected all cases of infarction admitted within 48 h of symptom onset in November 2000.

RESULTS

Among the 2320 patients included in the registry, 487 (21%) had diabetes, of whom 215 (44%) were on SU. Patients on SU were older and had a more frequent history of hyperlipidemia than those not receiving SU. Type and location of infarction were similar in the two groups, and there was no difference in Killip class on admission. In-hospital mortality was lower in patients on SU (10.2%) than in those without SU (16.9%) (p = 0.035). There was a trend toward less frequent ventricular fibrillation (2.3% vs 5.9%, p = 0.052). In two models of multivariate analyses, SU therapy was associated with decreased in-hospital mortality (model 1: relative risk: 0.44, p = 0.012; model 2: relative risk: 0.37, p = 0.020).

CONCLUSIONS

In this nationwide registry reflecting real-world practice, the use of sulfonylureas in diabetic patients was not associated with increased in-hospital mortality.

Effect of early initiation of statins on survival in patients with acute myocardial infarction (the USIC 2000 Registry)

We evaluated the association of statin initiation within 48 hours of admission for an acute myocardial infarction with a 1-year prognosis on a nationwide scale. Patients who received a statin within 48 hours of admission but not before hospitalization had an improved prognosis (hazard ratio 0.57, 95% confidence interval 0.38 to 0.86, p <0.007) after adjustment for covariates and propensity score.

Management and in-hospital outcome of patients with acute myocardial infarction admitted to intensive care units at the turn of the century: results from the French nationwide USIC 2000 registry

OBJECTIVE

To assess actual practices and in-hospital outcome of patients with acute myocardial infarction on a nationwide scale.

METHODS

Of 443 intensive care units in France, 369 (83%) prospectively collected data on all cases of infarction (within < 48 hours of symptom onset) in November 2000.

RESULTS

2320 patients (median age 68 years, 73% men) were included, of whom 83% had ST segment elevation infarction (STEMI). Patients without STEMI were older and had a more frequent history of cardiovascular disease. Median time to admission was 5.0 hours for patients with and 6.5 hours for those without STEMI. Reperfusion therapy was used for 53% of patients with STEMI (thrombolysis 28%, primary angioplasty 25%). In-hospital mortality was 8.7% (5.5% of patients without and 9.3% of those with STEMI). Multivariate analysis found that age, Killip class, lower blood pressure, higher heart rate on admission, anterior location of infarct, STEMI, diabetes mellitus, previous stroke, and no current smoking independently predicted in-hospital mortality. At hospital discharge, 95% received antiplatelet agents, 75% received beta blockers, and over 60% received statins. Angiotensin converting enzyme inhibitors were prescribed for 40% of the patients without and 52% of those with ST elevation.

CONCLUSIONS

This nationwide registry, including all types of centres irrespective of their size and experience, shows continued improvement in patient care and outcomes. Time from symptom onset to admission, however, has not improved in recent years and reperfusion therapy is used for just over 50% of patients with STEMI, with an increasing use of primary angioplasty.

Impact of Prehospital Thrombolysis for Acute Myocardial Infarction on 1-Year Outcome

Background— Limited data are available on the impact of prehospital thrombolysis (PHT) in the “real-world” setting.

Methods and Results— Of 443 intensive care units in France, 369 (83%) prospectively collected all cases of infarction (≤48 hours of symptom onset) in November 2000; 1922 patients (median age, 67 years; 73% men) with ST-segment–elevation infarction were included, of whom 180 (9%) received intravenous thrombolysis before hospital admission (PHT). Patients with PHT were younger than those with in-hospital thrombolysis, primary percutaneous interventions, or no reperfusion therapy. Median time from symptom onset to hospital admission was 3.6 hours for PHT, 3.5 hours for in-hospital lysis, 3.2 hours for primary percutaneous interventions, and 12 hours for no reperfusion therapy. In-hospital death was 3.3% for PHT, 8.0% for in-hospital lysis, 6.7% for primary percutaneous interventions, and 12.2% for no reperfusion therapy. One-year survival was 94%, 89%, 89%, and 79%, respectively. In a multivariate analysis of predictors of 1-year survival, PHT was associated with a 0.49 relative risk of death (95% CI, 0.24 to 1.00; P =0.05). When the analysis was limited to patients receiving reperfusion therapy, the relative risk of death for PHT was 0.52 (95% CI, 0.25 to 1.08; P =0.08). In patients with PHT admitted in ≤3.5 hours, in-hospital mortality was 0% and 1-year survival was 99%.

Conclusions— The 1-year outcome of patients treated with PHT compares favorably with that of patients treated with other modes of reperfusion therapy; this favorable trend persists after multivariate adjustment. Patients with PHT admitted very early have a very high 1-year survival rate.

Serial echocardiographic assessment of left ventricular mass

OBJECTIVES

In addition to the interest of mixing the sequence of echo-exam in a central blinded review, we studied the effect that might result from group-analysis of all echocardiograms simultaneously for each patient, with their sequence kept blind. A priori, this method of reading has the potential of decreasing measurement variability.

METHODS

We included 630 echocardiograms from 210 hypertensive patients participating in a randomized clinical trial comparing two antihypertensive agents for regression of left ventricular (LV) hypertrophy. Three echocardiograms per patient [selection (4 weeks before; W-4), at inclusion (week 0; W0), and the end of treatment (week 52; W52)], were read twice, according to two methods, blind to centre, patient numbers and sequence of visits: (1) examination of individual serial echocardiograms, (2) examination of all-patient mixed echocardiograms. The first method was expected to increase the power of treatment comparison by reducing variability of measurements of left ventricular mass (LVM).

RESULTS

Pooling echocardiograms of all patients reduces variability of LVM change under treatment: absolute LVM (W52 - W0) standard deviation was reduced by 22%. Nevertheless, despite a good between-methods agreement for LVM values at each visit (intra-class coefficient of correlation from 0.88 to 0.92), LVM change under treatment was reduced even more, by 41%. Thus, the slight decrease of variability induced by gathering the echocardiograms is associated with an even greater reduction of LVM change.

CONCLUSIONS

According to these findings, the 'full-blind' methodology for a central blinded review in clinical trials appears to produce the maximum power of the study with the lowest sample size.

[Value of the association of D-dimer measurement and the evaluation of clinical probability in a non-invasive diagnostic strategy of pulmonary embolism]

New diagnostic tools in suspected pulmonary embolism complete the classical diagnostic strategy of pulmonary scintigraphy and pulmonary angiography to limit the indications of these two invasive investigations. In a prospective series of 204 consecutive patients with suspected pulmonary embolism the association of D-dimer measurement and clinical probability was assessed for the exclusion of the diagnosis of pulmonary embolism. The D-DI Liatest is a new generation, unitary, rapid and quantitative latex test with a comparative diagnostic performance to that of the reference ELISA test, and well adapted to emergency situations.The clinical probability was assessed by a quantitative score based on past history, clinical symptoms and signs. The positive diagnosis of pulmonary embolism was made by spiral CT scanner and/or pulmonary angiography, associated with Duplex ultrasonography of the leg veins in nondiagnostic results. The prevalence of pulmonary embolism was 42.6% and the absence of anticoagulation in patients considered not to have pulmonary embolism was associated with a thrombo-embolic incidence of 0.9% at 3 months. Fifty-six patients had D-dimer concentrations equal or inferior to the threshold of 500 microg/L; the sensitivity was 99% and the specificity 47% with a negative predictive value of 98% to 100% in cases with a low clinical probability. D-dimer measurement is reliable and has a high cost-benefit value in ambulatory patients with suspected of pulmonary embolism and is even more valuable when the clinical probability of this diagnosis is low.

Évolution de la prise en charge et du pronostic de l'infarctus du myocarde en France entre 1995 et 2000 : résultats des études USIK 1995 et USIC 2000Evolution of the management and outcomes of patients admitted for acute myocardial infarction in France from 1995 to 2000: data from the USIK 1995 and USIC 2000 nationwide registries

We assessed the in-hospital management and short- and long-term outcomes of two series of patients admitted for acute myocardial infarction, 5 years apart, in France. The most recent cohort was younger and with a less frequent history of cardiac diseases, but was more often diabetic and with anterior infarcts. Five-day mortality significantly improved from 7.7% to 6.1% (P < 0.03) and 1-year survival was also less in the most recent period (15% versus 19%, P < 0.01). Multivariate analyses showed that the period of inclusion (2000 versus 1995) was an independent predictor of both short- and long-term mortality. In analyses restricted to the patients who were alive by day 5, initial treatment with statins was associated with a 38% decrease in the risk of death at 1 year. Likewise, in patients with left ventricular ejection fraction < or = 35%, the early prescription of ACE inhibitors was associated with a 41% reduction in the risk of 1-year mortality. Thus, in the real world setting, a continued decline in 1-year mortality is observed in patients admitted to intensive care units for recent acute myocardial infarction. This goes along with a shift in reperfusion therapy towards a broader use of coronary angioplasty and with an increased use of the early prescription of recognised secondary prevention medications.

[Calcified aortic stenosis with left ventricular dysfunction and low transvalvular gradients. Must one reject surgery in certain cases?]

The natural history of severe aortic stenosis (aortic valve area < 1 cm2 or < 0.6 cm2/m2) with left ventricular systolic dysfunction and low transvalvular gradients (mean gradient < 40 mmHg) is mediocre in the short term and the operative risk is high. Dobutamine echocardiography provides a reliable evaluation of the aortic obstacle by diagnosing the rare cases of relative aortic stenosis in which the valve surface area has been underestimated because of a low cardiac output (aortic surface area > 1.2 cm2 with a mean gradient < 30 mmHg with dobutamine): in this case, the limited available data suggests that medical therapy with strict follow-up of its efficacy is the best management. The other use of dobutamine echocardiography is to assess left ventricular contractile reserve, defined as a increase > or = 20% in stroke volume under dobutamine. Cases with a contractile reserve have an operative risk of 5 to 10% and the medium-term benefits of valve replacement have been demonstrated. In the absence of contractile reserve, the operative risk is much grater, 30 to 60%, and also depends on other parameters such as the mean basal transaortic pressure gradient (risk five times greater in cases with a mean gradient < 20 mmHg), the need for coronary bypass surgery and associated co-morbid conditions. The surgical contraindications are in fact relatively few and concern patients with several risk factors: absence of contractile reserve itself is not a definitive surgical contraindication.

Low-gradient aortic stenosis: operative risk stratification and predictors for long-term outcome: a multicenter study using dobutamine stress hemodynamics

BACKGROUND

The prognostic value of dobutamine stress hemodynamic data in the setting of low-gradient aortic stenosis has been addressed in small, single-center studies. Larger studies are needed to define the criteria for selecting the patients who will benefit from valve replacement.

METHODS AND RESULTS

Six centers prospectively enrolled 136 patients with aortic stenosis (96 men; median age, 72 years [range, 65 to 77 years]; median aortic valve area, 0.7 cm2 [range, 0.6 to 0.8]; mean transaortic gradient, 29 mm Hg [range, 23 to 34 mm Hg]; cardiac index, 2.11 L x min(-1) x m(-2) [range, 1.75 to 2.55 L x min(-1) x m(-2)]). Left ventricular contractile reserve on the dobutamine stress Doppler study was present in 92 patients (group I) and absent in 44 patients (group II). Operative mortality was 5% (3 of 64 patients) in group I compared with 32% (10 of 31 patients) in group II (P=0.0002). Predictors for operative mortality were the lack of contractile reserve (odds ratio, 10.9; 95% confidence interval [CI], 2.6 to 43.4; P=0.001) and a mean transaortic gradient < or =20 mm Hg (odds ratio, 4.7; 95% CI, 1.1 to 21.0; P=0.04). Predictors for long-term survival were valve replacement (hazard ratio, 0.30; 95% CI, 0.17 to 0.53; P=0.001) and left ventricular contractile reserve (hazard ratio, 0.40; 95% CI, 0.23 to 0.69; P=0.001).

CONCLUSIONS

In the setting of low-gradient aortic stenosis, surgery seems beneficial for most of the patients with left ventricular contractile reserve. In contrast, the postoperative outcome of patients without reserve is compromised by a high operative mortality. Thus, dobutamine stress Doppler hemodynamics may be factored into the risk-benefit analysis for each patient.