Antonio Nigri

Assessment of Flow Velocity Reserve by Transthoracic Doppler Echocardiography and Venous Adenosine Infusion Before and After Left Anterior Descending Coronary Artery Stenting

OBJECTIVES We sought to evaluate whether coronary flow velocity reserve (CFR) (the ratio between hyperemic and baseline peak flow velocity), as measured by transthoracic Doppler echocardiography during adenosine infusion, allows detection of flow changes in the left anterior descending coronary artery (LAD) before and after stenting. BACKGROUND The immediate post-stenting evaluation of CFR by intracoronary Doppler has shown mixed results, due to reactive hyperemia and microvascular stunning. Noninvasive coronary Doppler echocardiography may be a more reliable measure than intracoronary Doppler. METHODS Transthoracic Doppler echocardiography during 90-s venous adenosine infusion (140 microg/kg body weight per min) was used to measure CFR of the LAD in 45 patients before and 3.7 +/- 2 days after successful stenting, as well as in 25 subjects with an angiographically normal LAD (control group). RESULTS Adequate Doppler spectra were obtained in 96% of the patients. Pre-stent CFR was significantly lower in patients than in control subjects (diastolic CFR: 1.45 +/- 0.5 vs. 2.72 +/- 0.71, p < 0.01; systolic CFR: 1.61 +/- 1.02 vs. 2.41 +/- 0.68, p < 0.01) and increased toward the normal range after stenting (diastolic CFR: 2.58 +/- 0.7 vs. 2.72 +/- 0.75, p = NS; systolic CFR: 2.43 +/- 1.01 vs. 2.41 +/- 0.52, p = NS). Diastolic CFR was often damped, suggesting coronary steal in patients with > or =90% versus <90% LAD stenosis (0.86 +/- 0.23 vs. 1.69 +/- 0.43, p < 0.01). Coronary stenting normalized diastolic CFR in these two groups (2.45 +/- 0.77 and 2.64 +/- 0.69, respectively, p = NS), even though impaired diastolic CFR persisted in three of four patients with > or =90% stenosis. Stenosis of the LAD was better discriminated by diastolic (F = 49.30) than systolic (F = 12.20) CFR (both p < 0.01). CONCLUSIONS Coronary flow reserve, as measured by transthoracic Doppler echocardiography, is impaired in LAD disease; it may identify patients with > or =90% stenosis; and it normalizes early after stenting, even in patients with > or =90% stenosis.

Resting and ambulatory ECG predictors of mode of death in dilated cardiomyopathy

With the purpose of verifying whether the electrocardiogram (ECG) pattern alone can predict the mode of death in dilated cardiomyopathy, data from 12-lead ECGs and 48-hour arrhythmia monitoring were evaluated in 67 patients with dilated cardiomyopathy. During a mean follow-up period of 3 +/- 2 years, death from congestive heart failure occurred in 18 patients (27%), whereas 10 (15%) died suddenly (NS). Multivariate analysis showed that left bundle branch block (p < 0.001) and left atrial enlargement (p < 0.001) were independently related to death from congestive heart failure. Ventricular arrhythmias of Lown grade 4A or 4B (p < 0.001) and repolarization time, as assessed by QTc-QRS interval (p < 0.05), were independent predictors of sudden death. It is concluded that ECG features alone may be helpful for risk factor characterization of dilated cardiomyopathy patients, provided that multiple ECG criteria are utilized at time of diagnosis.

Histomorphometric features predict 1-year outcome of patients with idiopathic dilated cardiomyopathy considered to be at low priority for cardiac transplantation

Cardiac transplantation for patients with idiopathic dilated cardiomyopathy (IDC) and poor left ventricular function usually is postponed until symptoms have become intolerable. However, the short-term prognosis of this subset of patients has been defined poorly. Accordingly, the 1-year outcome was investigated in 30 patients with IDC with an ejection fraction < or = 25% who showed a stabilized clinical condition at assessment for transplantation and were therefore considered at low priority for surgery. During follow-up, 10 patients (group A) showed a poor outcome: 2 died suddenly, and 8 had hemodynamic failure (4 of whom underwent transplantation and 4 of whom died from heart failure while on the waiting list). The remaining 20 patients (group B) had a benign outcome. At assessment for cardiac transplantation, clinical and electrocardiographic features, left ventricular dimension, and ejection fraction were similar between the two groups. However, group A patients had higher left ventricular end-diastolic pressure (p < 0.03) and lower cardiac index (p < 0.02) and stroke volume index (p < 0.03) with respect to group B patients. In addition, the former had a lower myofibril volume fraction (p < 0.001) and a higher nuclear area (p < 0.001) compared with the latter. Multivariate analysis selected myofibril volume fraction (p < 0.001) and nuclear area (p < 0.005) as the only independent predictors of a poor 1-year outcome. The combination of myofibril volume fraction < or = 89% and nuclear area > 50 microns 2 was found in all group A patients (sensitivity 100%) but in only 2 group B patients (specificity 90%). It is concluded that in patients with IDC considered at low priority for cardiac transplantation: (1) the 1-year freedom from a cardiac event is lower than that currently expected with surgery; (2) histomorphometric features, that is, the concurrency of low myofibril volume fraction and increased nuclear area, predict short-term outcome; and (3) endomyocardial biopsy at assessment for cardiac transplantation might improve the rationalization of the timing of the procedure.

Electrocardiographic correlates with left ventricular morphology in idiopathic dilated cardiomyopathy

The purpose of the present study was to verify whether the electrocardiographic pattern of patients with idiopathic dilated cardiomyopathy (IDC) might be useful in predicting measurements of left ventricular (LV) morphology. A total of 12 electrocardiographic criteria for LV enlargement were evaluated in 67 patients with IDC, aged 14 to 68 years (mean 48), and were correlated to LV wall thickness, volume and mass, as assessed at angiography (all patients) and echocardiography (50 patients). Linear regression analysis showed weak correlations between multiple electrocardiographic criteria and LV wall thickness, volume and mass. Multiple logistic regression analysis showed that total 12-lead QRS amplitude, voltage criteria of Sokolow and Lyon, overshoot and U-wave inversion were the variables significantly related to LV wall thickness, as assessed by angiography (r = 0.55, p less than 0.005) and echocardiography (r = 0.43, p less than 0.025). The sum of T/R-wave ratios, the RV6/RV5 ratio and the Romhilt-Estes score were predictors of LV end-diastolic volume, as determined by angiography (r = 0.83, p less than 0.001) and echocardiography (r = 0.77, p less than 0.005). Total 12-lead QRS amplitude and the sum of T/R-wave ratios were the only independent predictors of LV mass, either angiographically (r = 0.81, p less than 0.001) or echocardiographically measured (r = 0.71, p less than 0.025). It is concluded that a single electrocardiographic criterion for prediction of LV morphology in patients with IDC is barely effective. Multiple electrocardiographic criteria should be utilized to better predict LV mass and distinguish reliably between LV wall thickening and dilatation.

Coronary Air Embolism Complicating Accessory Pathway Catheter Ablation: Detection by Echocardiography

Percutaneous radiofrequency catheter ablation has been recently introduced for treatment of Wolff-Parkinson-White syndrome. Access to left free-wall atrioventricular accessory pathways can be obtained either via retrograde cardiac catheterization or via the transseptal procedure, which allows ablation of the accessory pathway at its ventricular or atrial insertion, respectively. We describe a patient with Wolff-Parkinson-White syndrome in whom coronary air embolism occurred as a complication of transseptal percutaneous radiofrequency catheter ablation. The diagnosis was made by two-dimensional echocardiography showing a marked echocontrast effect in the posterior wall and in the posterior half of the interventricular septum. A grossly evident breakage of the rubber seal of the vascular sheath was supposed to be the cause of air insinuation. This report suggests that the transseptal approach should be used with caution in performing percutaneous radiofrequency catheter ablation to avoid the risk of air embolization. Two-dimensional echocardiography is an ideal tool to detect this complication.

Clinical significance of small left-to-right shunts after percutaneous mitral valvuloplasty.

Left-to-right shunt after percutaneous mitral valvuloplasty was evaluated by contrast echocardiography in 29 patients at 24 hours and at 1, 3, 6, and 9 months after the procedure. The patients were divided into two groups: in group A (13 patients) the double-balloon technique was used; in group B (16 patients) the Inoue single-balloon technique was used. The two groups were comparable in terms of age, gender, and mitral valve area before and after percutaneous mitral valvuloplasty. A left-to-right shunt was detected in all patients 24 hours after the procedure. At 1 month follow-up the shunt was present in 12 patients of group A (92%) and in 13 of group B (81%) with a statistically significant difference (p < 0.001). At 3 months the values were 7 (54%) in group A and 6 (37.5%) in group B (p < 0.05); at 6 months the values were 3 (23%) in group A and 3 (19%) in group B (NS). At 9 months a left-to-right shunt was no longer detectable in any of the patients in either group. The disappearance of the shunt could be related to a healing process of the atrial septal injury that occurs within a few months after percutaneous mitral valvuloplasty. This process seems to be more rapid in group B patients, probably because of the smaller lesion that is produced in the atrial septum by the passage of the Inoue balloon.

Intraoperative percutaneous double-balloon valvuloplasty versus surgical commissurotomy for mitral valve stenosis

I n patients with pure mitral stenosis, a significant inThe study population consisted of 10 patients (4 men crease in valvular area can be obtained by a percutaneand 6 women, mean age 46 f 8 years) with severe pure ous approach with balloon valvuloplasty, by surgical mitral stenosis (mitral valve regurgitation <grade 1 closed commissurotomy, and by a selective eye-guided of Sellers classification), no or mild leafret calcium reparative procedure during cardiopulmonary bypass. and Block echocardiographic score 18. Patients with The surgical closed mitral commissurotomy for treatmarked dysfunction of the subvalvular apparatus were ment of mitral stenosis was first described by Cutler in excludedfrom the study. Allpatients underwent double1924 and is still the most common surgical procedure in balloon dilatation of the mitral valve and subsequently most countries. The open surgical commissurotomy, surgical open commissurotomy during cardiopulmonary more recently introduced, together with the mitral valve bypass. replacement represent a more appropriate choice in paDuring cardiopulmonary bypass the left atrium was tients with leaflet calcification, subvalvular disease or left opened, the mitral valve inspected and its area measured atria1 thrombus. Percutaneous balloon mitral valvuloby a Hegar calibrator. Two balloons (20 and 15 mm in plasty was first described by Inoue et all in 1984 as a diameter) were advanced across the mitral valve and nonsurgical therapeutic approach to surgical commissursimultaneously inflated with saline solution at 5 atm, otomy in patients with pure mitral stenosis. Al Zaibag et After the procedure the surgeon performed a complete al* subsequently developed the double-balloon technique reparative procedure opening the commissures not yet to obviate the noncommercial availability of the Inoue split and mobilizing tendinous cords and papillary muscatheter. Under similar anatomic conditions, open-chest cles. Measurements of valve area were obtained after commissurotomy should be more effective in terms of balloon valvuloplasty and after surgical commissurfinal valvular area than techniques such as closed cornotomy. missurotomy or percutaneous balloon valvuloplasty that A 2-tailed Student’s t test was used to test the dtfferinduce a rude mechanical stress to the mitral commisences between interventions. Ap value <0.05 was considsures and leaflets. It has been recently suggested, howered significant. Results are expressed as mean f I ever, that balloon valvuloplasty provides hemodynamic standard deviation. results comparable to those obtained by either surgical Double-balloon valvuloplasty caused splitting of open or closed commissurotomy.3 The present study comboth commissures in Spatients, whereas only the anteropares intraoperative effects on final mitral valve area, as lateral commissures were opened in the remaining 5 paassessed by a Hegar calibrator, of percutaneous doubletients. The valve area increasedfrom I Sl f 0.24 to 3.28 balloon mitral valvuloplasty and open-chest commissurf 0.48 cm2 Cp <O.OOl) after double-balloon valvulootomy. plasty and to 5.2 f 0.56 cm2 after the surgicalprocedure From the Department of Cardiology and Cardiovascular Surgery, Uni@ <O.OOl compared with valvuloplasty) (Figure 1). No versity “La Sapienza” Rome, Italy. Manuscript received December 12, damage of the valvular apparatus was evident after dou1991; revised manuscript received April 2,1992, and accepted April 4. ble-balloon dilatation in any patient.

Evidence for improved cardiac performance after beta-blockade in patients with coronary artery disease.

The study was undertaken to investigate the acute haemodynamic effects of bunitrolol (0-2-hydroxy-3-(tert.butylamino)-propoxy)-benzonitril-hydrochloride), a cardioselective beta-blocker with partial agonist activity. Right and left heart catheterization was performed in eleven patients with documented coronary artery disease. After bunitrolol (10 mg i.v.), there was a statistically significant decrease in left ventricular and aortic systolic pressures, left ventricular end-diastolic pressure, aortic diastolic and mean pressures, pressure-rate product and compliance index (△P/△V). Left ventricular dp/dt, left ventricular dp/dt over isovolumic pressure, systemic resistance and heart rate tended to decrease, stroke volume and left ventricular stroke work index tended to increase, without statistical significance. Cardiac index showed individual variations, the mean values for the group being unchanged. Correlation of left ventricular end-diastolic pressure and left ventricular stroke work index showed a shift toward improved ventricular function curve in most cases, deterioration in no instance. Supine exercise was performed in ten patients. Angina occurred in nine patients; in five only before and in four before and after beta-blockade. Post-drug exercise heart rate, pressure-rate product and left ventricular end-diastolic pressure were significantly lower, the latter also in the four patients who still presented exercise angina. It is concluded that certain beta-blockers can improve cardiac performance at rest and during exercise in patients with coronary artery disease. This is explainable on the basis of a more favourable balance between oxygen supply and demand, together with a less marked negative inotropic effect due to the partial agonist activity of the agent used in the study.