Atrial septostomy in the treatment of severe pulmonary arterial hypertension

BACKGROUND

Atrial septostomy (AS) may improve symptoms and haemodynamics in patients with severe pulmonary arterial hypertension (PAH).

METHODS

Twenty AS performed in 17 patients with severe progressive PAH (13 primary pulmonary hypertension, two collagen vascular disease, one thromboembolic disease, one vaso-occlusive disease) were analysed. Seven patients were in NYHA class III and 10 in NYHA IV. Fifteen patients were on long term prostanoid treatment. AS was performed under fluoroscopy using graded balloon technique.

RESULTS

AS improved clinical symptoms and increased the cardiac index from 1.8 to 2.2 l/min/m(2) and systemic oxygen transport from 263.2 to 329.6 ml/min/m(2) (p<0.001). Procedure related complications included one non-fatal atrial puncture and one unsuccessful septal puncture. Four patients died within 1 week of surgery from uncontrolled tachyarrhythmia (n=1), severe hypoxaemia (n=1), and multiorgan failure (n=2). One further patient died after voluntarily discontinuing renal dialysis. Twelve patients are alive 5-17 months after the operation with five patients undergoing heart-lung transplantation. There were no differences in haemodynamic and functional parameters between the non-survivors and the mid term survivors. However, the non-survivors were significantly older (52 v 36 years, p<0.01) and had a significantly lower creatinine clearance rate (70 ml/min v 48 ml/min, p<0.05).

CONCLUSION

Atrial septostomy improves clinical symptoms, cardiac index, and systemic oxygen transport and has the potential to influence the prognosis in selected cases of severe PAH.

Ostial left anterior descending coronary artery stent positioning: partial preinflation prevents stent oscillation and facilitates accurate deployment

Ostial intracoronary stent deployment is complicated by the influence of cardiac motion, which causes the stent to oscillate back and forth during the cardiac cycle. Accurate deployment can be facilitated by initial low pressure inflation of the balloon on which the stent is mounted. This stabilizes the stent within the stenosis, while still allowing adjustment of the exact stent location prior to deployment.

Coronary flow reserve improves after aortic valve replacement for aortic stenosis: an adenosine transthoracic echocardiography study

OBJECTIVES

The goal of this study was to assess coronary flow reserve (CFR) before and after aortic valve replacement (AVR).

BACKGROUND

Coronary flow reserve is impaired under conditions of left ventricular (LV) hypertrophy. It is not known whether CFR improves with regression of LV hypertrophy in humans.

METHODS

We investigated 35 patients with pure aortic stenosis, LV hypertrophy and normal coronary arteriograms. Patients underwent adenosine transthoracic echocardiography on two occasions--immediately before AVR and six months postoperatively. Left ventricular mass, distal left anterior descending coronary artery (LAD) diameter, flow and CFR were assessed on each occasion.

RESULTS

Distal LAD diameter was successfully imaged in 30 patients (86%), and blood flow was successfully imaged in 27 (77%). Paired data were subsequently available in 24 patients, of whom 14 were men, mean age 68.1+/-12.5 years, body mass index 24.5+/-2.0 kg/m2, aortic valve gradient 93+/-32 mm Hg. Pre- to post-AVR a significant decrease was seen in LV mass (271+/-38 vs. 236+/-32g, p<0.01) and LV mass index (154+/-21 vs. 134+/-21 g/m2, p< 0.01). Distal LAD diameter fell from 2.27+/-0.37 to 2.23+/-0.35 mm, p = 0.08). Pre- to post-AVR there was no significant change in resting parameters of peak diastolic velocity (0.43+/-0.16 vs. 0.41+/-0.11 m/s), distal LAD flow 23.3+/-10.1 vs. 20.9+/-5.2 ml/min or distal LAD flow scaled for LV mass (8.7+/-3.8 vs. 9.0+/-2.5 ml/min/100 g LV mass), but there was significant increase in hyperemic peak diastolic velocity (0.71+/-0.26 vs. 1.08+/-0.24 m/s; p<0.01), distal LAD flow (37.8+/-11.3 vs. 53.5+/-16.1 ml/min; p<0.01) and distal LAD flow scaled for LV mass (14.3+/-5.0 vs. 23.3+/-8.5 ml/min/100 g LV mass; p<0.01). Coronary flow reserve, therefore, increased from 1.76+/-0.5 to 2.61+/-0.7.

CONCLUSIONS

Coronary flow reserve increases after AVR for aortic stenosis. This increase occurs in tandem with regression of LV hypertrophy.

Coronary flow reserve is supranormal in endurance athletes: an adenosine transthoracic echocardiographic study

OBJECTIVE

To compare coronary flow reserve in endurance athletes and healthy sedentary controls, using adenosine transthoracic echocardiography.

METHODS

29 male endurance athletes (mean (SD) age 27.3 (6.6) years, body mass index (BMI) 22.1 (1.9) kg/m(2)) and 23 male controls (age 27.2 (6.1) years, BMI 23.9 (2.6) kg/m(2)) with no coronary risk factors underwent transthoracic echocardiographic assessment of distal left anterior descending coronary artery (LAD) diameter and flow, both at rest and during intravenous adenosine infusion (140 microg/kg/min).

RESULTS

Distal LAD diameter and flow were adequately assessed in 19 controls (83%) and 26 athletes (90%). Distal LAD diameter in athletes (2.04 (0.25) mm) was not significantly greater than in sedentary controls (1.97 (0.27) mm). Per cent increase in LAD diameter following 400 microg sublingual nitrate was greater in the athletes than in the controls, at 14.1 (7. 2)% v 8.8 (5.7)% (p < 0.01). Left ventricular mass index in athletes exceeded that of controls, at 130 (19) v 98 (14) g/m(2) (p < 0.01). Resting flow among the athletes (10.6 (3.1) ml/min; 4.4 (1.2) ml/min/100 g left ventricular mass) was less than in the controls (14.3 (3.6) ml/min; 8.2 (2.2) ml/min/100 g left ventricular mass) (both p < 0.01). Hyperaemic flow among the athletes (61.9 (17.8) ml/min) exceeded that of the controls (51.1 (14.6) ml/min; p = 0.02), but not when corrected for left ventricular mass (25.9 (5.6) v 28.5 (7.4) ml/min/100 g left ventricular mass; NS). Coronary flow reserve was therefore substantially greater in the athletes than in the controls, at 5.9 (1.0) v 3.7 (0.7) (p < 0.01).

CONCLUSIONS

Coronary flow reserve in endurance athletes is supranormal and endothelium independent vasodilatation is enhanced. Myocardial hypertrophy per se does not necessarily impair coronary flow reserve. Adenosine transthoracic echocardiography is a promising technique for the investigation of coronary flow reserve.

Inoue balloon mitral valvuloplasty: long-term clinical and echocardiographic follow-up of a predominantly unfavourable population

AIMS

To assess long-term outcome in a typical Western population of predominantly unfavourable patients undergoing Inoue balloon mitral valvuloplasty. Outcome amongst patients has only been undertaken in the medium term. Long-term echocardiographic data in particular are scarce.

METHODS

Inoue mitral valvuloplasty was attempted in 106 patients. There were six technical failures; the procedure was therefore completed in 100 patients, who underwent annual clinical and echocardiographic follow-up.

RESULTS

Patients were aged 63.5+/-10. 3 years. 82% were female. Unfavourable characteristics included age >65 (52%), NYHA class III or IV (87%), >/=1 significant co-morbidity (63%), atrial fibrillation (82%), previous surgical commissurotomy (25%) and echocardiographic score >8 (59%, mean 8.9+/-2.1). Mitral valve area increased from 0.98+/-0.23 to 1.54+/-0.31 cm(2). There were three major complications. Post-procedure, symptoms improved in 88% of patients. Haemodynamic success (mitral valve area increase >50%, final mitral valve area >1.5 cm(2), mitral regurgitation </=grade 2) was achieved in 61% of cases. Mean follow-up was 4.3+/-1. 4 years. Survival was 97%, 88% and 82% at 1, 3 and 6 years. Event-free survival (freedom from death, mitral valve replacement or repeat valvuloplasty) was 96%, 82% and 56% at 1, 3 and 6 years. Freedom from restenosis (loss of >50% gain in mitral valve area, mitral valve area <1.5cm (2)) was 98%, 92% and 75% at 1, 3 and 6 years. Pre-procedural predictors of event-free survival were male sex, absence of co-morbidities, lower echocardiographic score and smaller left atrial diameter.

CONCLUSIONS

In a Western population with predominantly unfavourable characteristics for mitral valvuloplasty, long-term outcome post-procedure is reasonable. A moderate increase in mitral valve area can be achieved at low procedural risk, and the subsequent rate of restenosis is low. Nonetheless, 6 years after the procedure, half of the patients will have required further intervention or died. For fitter patients willing to accept significant operative risk, mitral valve replacement remains a valuable alternative.

Noninvasive indexes of left atrial diastolic function in hypertrophic cardiomyopathy

OBJECTIVES

Our goal was to noninvasively assess left atrial diastolic function and its relation to the impaired left ventricular filling in patients with hypertrophic cardiomyopathy.

METHODS AND RESULTS

We studied 34 patients with hypertrophic cardiomyopathy, 26 patients with secondary forms of left ventricular hypertrophy (aortic stenosis, fixed subaortic stenosis, hypertension), and 21 control subjects. Left atrial diastolic function was assessed by measuring acceleration time (SAT), deceleration time (SDT), and the EF (mean deceleration rate) slope of the pulmonary venous flow systolic wave (SW). Left ventricular diastolic function assessed by transmitral Doppler included peak early left ventricular and peak atrial filling velocities, the ratio of early-to-late peak velocities, isovolumic relaxation time, deceleration time, and EF slope. In patients with hypertrophic cardiomyopathy, acceleration time was significantly reduced (P<.05), deceleration time was significantly prolonged (P<.0001), and EF slope was significantly reduced (P<.01). These indexes were similar among the other two groups. No statistically significant difference existed between the subgroups of hypertrophic cardiomyopathy in the above indexes. Patients with hypertrophic cardiomyopathy and secondary forms of left ventricular hypertrophy had evidence of left ventricular diastolic dysfunction. In patients with hypertrophic cardiomyopathy, no correlation existed between left atrial and left ventricular diastolic function indexes (r = -0.26 to 0.33).

CONCLUSIONS

Echocardiographic indexes of left atrial relaxation and filling are abnormal in patients with hypertrophic cardiomyopathy but not in secondary forms of left ventricular hypertrophy. These indexes are abnormal in all forms of hypertrophic cardiomyopathy irrespective of left ventricular outflow tract obstruction and distribution of hypertrophy; they are not solely attributable to left ventricular diastolic dysfunction. The above may imply that hypertrophic cardiomyopathy is a cardiac myopathic disease that involves the heart muscle as a whole, irrespective of distribution of hypertrophy and obstruction.

Comparison of central venous and inferior vena caval pressures

Inferior vena caval pressures were measured in 60 patients undergoing cardiac catheterization and compared with central venous pressure from within the right atrium. Mean pressures within the abdominal inferior vena cava were essentially the same as mean right atrial pressure, suggesting that the inferior vena cava provides a useful safe alternative for measuring central venous pressure.

Pulmonary capillary wedge pressure in mitral stenosis accurately reflects mean left atrial pressure but overestimates transmitral gradient

Current opinion varies as to whether pulmonary capillary wedge pressure assessment of transmitral gradient in mitral stenosis is accurate; we therefore compared transmitral gradient in 36 patients awaiting balloon valvuloplasty using both pulmonary capillary wedge pressure and direct left atrial pressure. Mean pulmonary capillary wedge pressure correlated well with mean left atrial pressure (limits of agreement -1.5 to +3.7 mm Hg), but mean diastolic mitral gradient calculated using pulmonary capillary wedge pressure differed significantly from that calculated using left atrial pressure (limits of agreement -1.2 to +9.8 mm Hg): wedge pressure-assessed transmitral gradient is therefore misleading, routinely overestimating stenosis severity.

Coronary angiography in the presence of peripheral vascular disease: femoral or brachial/radial approach?

Peripheral vascular disease is considered a relative contraindication to the femoral approach for coronary angiography, but no data exist comparing the femoral and brachial/radial routes under these circumstances. We examined the influence of vascular approach on outcome. Two hundred and ninety-seven patients, mean age 67.1 +/- 8.4 years, with clinical or radiographic evidence of aortofemoral peripheral arterial disease underwent diagnostic coronary angiography during a 3-year period at this cardiothoracic center. The approach was successful in 121 of 154 femoral cases (79%) compared with 130 of 143 brachial/radial cases (91%; P < 0.01). Of the 33 failed femoral cases, 15 were then approached from the other femoral artery, with success in 6 (40%), while 18 were approached from the arm, with success in all (100%; P < 0.01). Brachial/radial cases took significantly longer than femoral cases (51 +/- 19 vs. 42 +/- 22 mins; P < 0.01). In cases where the femoral pulse was considered normal, the femoral approach nonetheless failed in 19 of 95 (20%). Major vascular complications (e.g., pulseless limb, arterial dissection, hemorrhage, or false aneurysm) occurred in nine femoral cases vs. zero brachial/radial cases (P < 0.01). Patients with peripheral vascular disease who undergo coronary angiography from the femoral artery have a 1-in-5 risk of procedural failure, necessitating use of an alternative vascular approach, and a 1-in-20 risk of a major vascular complication. Normality of femoral arterial pulsation is not a good predictor of femoral success. Brachial/radial approaches take longer, but succeed more frequently and have a negligible major vascular complication rate. We believe that patients with peripheral vascular disease should undergo coronary angiography via brachial or radial approach. Cathet. Cardiovasc. Intervent. 49:32-37, 2000.

Potential use of transthoracic echocardiography in the assessment of coronary flow reserve

Coronary flow reserve provides a gold standard assessment of the epicardial and microvascular coronary circulation. However, measurement of coronary flow reserve is limited by the invasiveness or complexity of the methods hitherto available. We investigated whether transthoracic echocardiography could be used to assess coronary flow reserve. We imaged distal left anterior descending coronary artery diameter and flow in 14 healthy volunteers, both at rest and during intravenous infusion of adenosine (140 microg/kg per minute). Volunteers were men, with an average (+/-SD) age of 28.4 +/- 6.3 years. Complete data were acquired in 11 cases. Average distal left anterior descending coronary artery diameter was 0.213 +/- 0.03 cm. Velocity time integral rose from 8.6 +/- 2.1 cm to 27.7 +/- 5.6 cm with adenosine infusion. Heart rate rose from 64.7 +/- 9. 8 to 75.3 +/- 11.7 bpm. The Doppler angle of incidence to flow was 42.4 +/- 8.7 degrees. Resting distal left anterior descending coronary artery flow was therefore calculated as 13.4 +/- 3.2 mL/min and hyperemic flow as 51.2 +/- 16.2 mL/min, yielding a coronary flow reserve of 3.81 +/- 0.6. We conclude that coronary flow reserve can be assessed in a selected population with the use of transthoracic echocardiography and an intravenous infusion of adenosine. The simplicity of this noninvasive technique suggests that it could become a useful tool for measurement of coronary flow reserve if imaging success rates can be optimized.

Balloon mitral valvuloplasty: comparison of haemodynamic and echocardiographic assessment of mitral stenosis at different heart rates in the catheterisation laboratory

AIMS

To compare echo-Doppler, Gorlin equation and haemodynamic methods of measuring mitral valve stenosis during right ventricular pacing-induced tachycardia before and after Inoue balloon mitral valvuloplasty to determine which method gave the most consistent results.

METHODS AND RESULTS

Measurements were made before and after valvuloplasty at: baseline heart rates, paced at 115 and then 145 beats/min. Mitral valve area by echo-Doppler was 1.1(+/-0.1) cm2 (mean +/- S.E.) before and 1.8(+/-0.2) cm2 after valvuloplasty; and by Gorlin equation: 0.9(+/-0.1) cm2 before and 1.5(+/-0.1) cm2 after. Echo-Doppler measurements were heart rate dependent but those by Gorlin measurements were not. At baseline, cardiac index was 2.08(+/-0.2) l min(-1), left atrial pressure 23.3(+/-7.9) mm Hg and mean mitral diastolic gradient 16.9(+/-9.9) mm Hg. After valvuloplasty, cardiac index was 2.31(+/-0.1) l min(-1), left atrial pressure fell to 19.2(+/-5.6) mm Hg and mean diastolic gradient was reduced to 8.5(+/-1.8) mm Hg.

CONCLUSIONS

The Gorlin mitral valve area appeared to be the most heart rate independent indicator of success following valvuloplasty.

Transthoracic echocardiographic measurement of coronary artery diameter: validation against quantitative coronary angiography

There has been no in vivo validation of the use of transthoracic echocardiography to measure distal left anterior descending coronary artery (LAD) diameter. We therefore undertook transthoracic echocardiography on 65 male patients immediately before cardiac catheterization to compare echocardiographic and angiographic findings. The distal LAD was successfully imaged in 41 (63%) patients; 29 of these had an angiographically normal distal LAD as assessed by an independent cardiologist and formed the study group. Transthoracic echocardiographic and quantitative coronary angiographic measurements of distal LAD diameter were made. Echocardiographic measurements ranged from 0.14 to 0.28 cm (mean 0.20 cm). Angiographic results ranged from 0.12 to 0.28 cm (mean 0.195 cm). Correlation between techniques was good (r=.925). The maximum discrepancy between transthoracic echocardiography and quantitative coronary angiography was 0.03 cm. Limits of agreement were +0.032 to -0.024 cm. We conclude that transthoracic echocardiography is a valid technique for measurement of distal LAD diameter.

Late complications following permanent pacemaker implantation or elective unit replacement

OBJECTIVE

To determine the rate of late complications following first implantation or elective unit replacement of a permanent pacemaker system.

DESIGN

Analysis of pacemaker data and complications prospectively acquired on a computerised database. Complications were studied over an 11 year period from January 1984 to December 1994.

SETTING

Tertiary referral cardiothoracic centre.

PATIENTS

Records of 2621 patients were analysed retrospectively.

MAIN OUTCOME MEASURES

Complications requiring repeat procedures occurring more than six weeks after pacemaker implantation or elective unit replacement.

RESULTS

The overall rate of late complications was significantly lower after first implantation of a permanent pacemaker (34 cases, complication rate 1.4%, 95% confidence interval 0.9% to 1.9%) than after elective unit replacement (16 cases, complication rate 6.5% (3.3% to 9.7%). There were 20 cases of erosion, 18 infections, five electrode problems, and seven miscellaneous problems. Complications were more common with inexperienced operators (18.9% (6.0% to 31.8%)) than with experienced operators (0.9% (0.3% to 1.5%).

CONCLUSIONS

The incidence of late complications following pacemaker implantation is low and compares favourably with early complication rates. The majority are caused by erosion and infection. Patients who have undergone elective unit replacement are at particular risk.

Balloon mitral valvuloplasty employing double transseptal puncture

Patients with mechanical aortic valve prostheses occasionally develop subsequent mitral stenosis and present as candidates for further intervention. Repeat thoracotomy in such patients carries considerable operative risk, but the traditional alternative of balloon mitral valvuloplasty with transaortic intraventricular monitoring is not feasible because mechanical aortic prostheses cannot be safely crossed at catheterization. We have therefore developed a technique for performing the procedure via double transseptal puncture. We present the technique and our experience of its use in four patients with mechanical aortic prostheses presenting for balloon mitral valvuloplasty.

Coronary angiography from the radial artery--experience, complications and limitations

AIMS

to assess the outcomes, complications and limitations of coronary angiography performed via percutaneous radial artery puncture.

METHODS AND RESULTS

two hundred and fifty patients underwent diagnostic coronary angiography from the radial artery, 182 (72.8%) of whom had contraindications to the femoral approach, for example due to peripheral vascular disease (n=85), therapeutic anticoagulation (29), or failed femoral approach (17). Procedural success in this high-risk population was achieved in 231 patients (92.4%). Principle reasons for failure were unsuccessful radial access (5) and arterial spasm (5). Procedure duration (SD) for an operator's first 20 cases compared with cases thereafter (min) was 47.7 (16.7) vs. 41.5 (14.6), P=0.0004; fluoroscopy time (min) 9.7 (7.1) vs. 6.6 (5.1), P=0.0001 and procedural success 89.6% vs. 94.1%, P=ns. Complications included two deaths associated temporally with catheterisation, three cases of arterial dissection without ischaemic sequelae and one transient ischaemic attack.

CONCLUSIONS

coronary angiography can be performed successfully from the radial artery, but this approach has limitations, which include the need to demonstrate dual palmar vascular supply, the prolonged learning phase, the procedural failure rate, patient discomfort and a demonstrable incidence of vascular and haemodynamic complications. We believe that radial coronary angiography should only be undertaken when there is a contraindication to the femoral approach.

Conservative operation for infective endocarditis of the mitral valve

BACKGROUND

Subvalvular preservation is necessary to maintain left ventricular function, but accidental retention of infected tissue could cause postoperative endocarditis.

METHODS

We examined 71 consecutive patients who underwent operation for mitral endocarditis. Endocarditis was uncontrolled and active in 24 patients, partially treated (unfinished antibiotic course) in 17, and healed in 30.

RESULTS

Valves were repaired in 17% versus 59% versus 63% and replaced with subvalvular preservation in 25% versus 6% versus 3% of the uncontrolled active, partially treated, and healed groups, respectively. Thirty-day mortality was 29% versus 0% versus 3.3% (p=0.003), total mortality was 46% versus 18% versus 17% (p=0.035), and complications-related mortality was 38% versus 11% versus 13% (p=0.054), respectively. There was a trend toward lower complications-related mortality with subvalvular preservation than without. Postoperative endocarditis occurred in 3 of 30 patients without and 1 of 41 patients with subvalvular preservation.

CONCLUSIONS

Postoperative mortality in uncontrolled active mitral endocarditis remains high, but results are good with partially treated or healed endocarditis. Subvalvular preservation improves outcome, does not increase postoperative endocarditis rates, and should be performed whenever feasible.

Ventricular pacemaker upgrade: experience, complications and recommendations

OBJECTIVE

To assess outcomes of pacemaker upgrade from single chamber ventricular to dual chamber.

DESIGN

Retrospective analysis of patients undergoing the procedure.

SETTING

Specialist cardiothoracic unit.

PATIENTS

44 patients (15 female, 29 male), mean (SD) age at upgrade 68.2 (12.9) years.

INTERVENTIONS

Upgrade of single chamber ventricular to dual chamber pacemaker.

MAIN OUTCOME MEASURES

Procedure duration and complications.

RESULTS

Principal indications for upgrade were pacemaker syndrome (17), "opportunistic"--that is, at elective generator replacement (8), heart failure (7), non-specific breathlessness/fatigue (7), and neurally mediated syncope (3). Mean (SD) upgrade procedure duration (82.9 (32.6) minutes) significantly exceeded mean VVI implantation duration (42.9 (13.3) minutes) and mean DDD implantation duration (56.6 (22.7) minutes) (both p < 0.01). Complications included pneumothorax (1), ventricular arrhythmia requiring cardioversion (2), protracted procedure (10), atrial lead repositioning within six weeks (8), haematoma evacuation (1), superficial infection (1), and admission to hospital with chest pain (1); 20 patients (45%) suffered one or more complications including four of the eight who underwent opportunistic upgrade.

CONCLUSIONS

Pacemaker upgrade takes longer and has a higher complication rate than either single or dual chamber pacemaker implantation. This suggests that the procedure should be performed by an experienced operator, and should be undertaken only if a firm indication exists. Patients with atrial activity should not be offered single chamber ventricular systems in the belief that the unit can be upgraded later if necessary at minimal risk.

Comparison of radial versus brachial approaches for diagnostic coronary angiography when the femoral approach is contraindicated

One hundred patients with contraindications to the femoral approach were randomized to undergo diagnostic coronary angiography via percutaneous radial puncture or brachial artery cutdown. Procedure duration, fluoroscopy time, and total radiation dose were significantly less via the radial route, whereas procedural success, complication rates, and pain scores were comparable; we conclude that the radial technique should be the arm approach of choice for new trainees, although there will be occasions when radial access fails and a brachial approach is required.

Noninvasive analysis of coronary artery poststenotic flow characteristics by using transthoracic echocardiography

This study was performed (1) to test whether transthoracic echocardiography may detect coronary flow velocity in the left anterior descending coronary artery distal to stenoses; and (2) to noninvasively assess coronary artery hemodynamics distal to coronary artery stenoses. High-frequency transthoracic echocardiography was used to assess blood velocity patterns in the distal segment of the left anterior descending coronary artery of 128 consecutive patients (mean age, 58 +/- 9 years; 97 men and 31 women) who underwent cardiac catheterization for investigation of angina. Biphasic, diastolic predominant Doppler velocity patterns were obtained in 67 patients (52%). There was no significant difference in any measurements of systolic blood velocity between patients with unobstructed (less than 30% stenosis) left anterior descending coronary artery, moderate stenosis (30% to 70% obstruction), or severe stenosis (more than 70% obstruction). Patients with severe stenosis demonstrated a reduction in the diastolic component of blood flow velocity in the distal left anterior descending coronary artery compared with patients in the other two groups. This technique may be useful for the noninvasive assessment of the significance of stenotic left anterior descending coronary artery disease or the outcome of interventional procedures.

Analysis of phasic flow velocity dynamics in the left anterior descending coronary artery before and after angioplasty using transthoracic echocardiography in patients with stable angina pectoris

High-frequency transthoracic Doppler echocardiography was used to determine the effects of significant stenosis on distal coronary blood flow velocity profiles. Before coronary angioplasty there was a reduction in diastolic and systolic flow and diastolic/systolic peak velocity ratio. After successful angioplasty velocity ratios returned to normal.

A quantitative description of dynamic left ventricular geometry in anaesthetized rats using magnetic resonance imaging

We report a functional application of magnetic resonance imaging (MRI) for the quantitative description of left ventricular geometry through systole and diastole in normal anaesthetized Wistar rats that might be applicable for the analysis of chronic changes resulting from pathological conditions. Images of cardiac anatomy were acquired through planes both parallel and perpendicular to the principal cardiac axis at times that were synchronized to the R wave of the electrocardiogram. The images of the transverse sections were assembled into three-dimensional representations of left ventricular geometry at consecutive time points through the cardiac cycle. This confirmed the geometrical coherence of the data sets, that each slice showed circular symmetry, and that the images were correctly aligned with the appropriate anatomical axes. Different models for the three-dimensional geometry of the left ventricle were then tested against the epi- and endocardial surfaces reconstructed from images of the transverse sections of the left ventricle in both systole and diastole using least-squares minimizations in three dimensions. In agreement with previous reports in the human heart, an elliptical figure of revolution offered an optimal fit to the epicardial and endocardial geometry for the rat heart in diastole. This was in preference to models that used spherical, quartic or parabolic geometries. However, in contrast to contraction in the human heart, all these geometrical representations broke down during systolic ejection in the rat heart. We therefore introduced a more general hybrid model which described left ventricular geometry in terms of the variation of the radii r(z), independently determined for each slice, with its position z along the principal cardiac axis. The resulting function r(z) could then be described by a simple ellipsoid of revolution not only during diastole, but also throughout ventricular ejection. The findings also ruled out alternative geometrical representations. It was then possible additionally to reconstruct the luminal and total left ventricular volumes, wall thicknesses and ejection fractions through the cardiac cycle and to confirm that the predicted total ventricular wall volume was conserved throughout the cardiac cycle. Our hybrid model of cardiac geometry may thus be useful for non-invasive serial studies of chronic pathological changes that use the rat as a model experimental system.

The morphologic consequences of systemic training

The development of echocardiography in the 1970s led to the flourishing of the study of the athlete's heart. From the earliest studies, it was apparent that athletes develop enlargement of the left ventricular cavity and thickening of myocardium in response to prolonged repetitive training. The changes in echocardiographic measurements are small and often within quoted normal ranges. By comparison to sedentary controls, however, left ventricular end-diastolic dimension is increased by approximately 10%, posterior wall dimension by 15% to 20%, and calculated mass by up to 45%.

Transient ST-segment changes associated with mitral valvuloplasty using the Inoue balloon

We describe unexplained transient inferior ST-segment elevation on the electrocardiogram during Inoue mitral valvuloplasty in 8 patients from a series of 108. Electrocardiographic changes were associated with chest pain in 7 patients, and although the clinical features were suggestive of myocardial ischemia, no cause for this could be found.

Transthoracic Doppler echocardiographic analysis of phasic coronary blood flow velocity in hypertrophic cardiomyopathy

OBJECTIVE

To use transthoracic Doppler echocardiography to assess coronary blood flow non-invasively in patients with hypertrophic cardiomyopathy.

DESIGN

High frequency transthoracic Doppler echocardiography was used to assess resting phasic coronary velocity patterns in patients with hypertrophic cardiomyopathy and to define the relation between coronary flow patterns and clinical, echocardiographic, and haemodynamic manifestations of this condition.

SETTING

A tertiary referral cardiothoracic centre.

METHODS

Fifteen patients (10 men and five women, mean (SD) age 49 (10.3) years) with asymmetric hypertrophic cardiomyopathy underwent high frequency (5 MHz) transthoracic Doppler echocardiographic assessment of the left anterior descending coronary artery. In addition, standard two dimensional echocardiography was performed. The results were compared with 16 normal participants (nine men and seven women, mean age 61.2 (10.7) years) who had no evidence of cardiac disease.

RESULTS

Biphasic diastolic predominant coronary artery blood velocity profiles were obtained in all patients and controls. Systolic peak blood velocity and velocity time integral were significantly reduced in the hypertrophic cardiomyopathy group compared with controls (11.3 (15.8) cm/s and 1.09 (1.78) cm v 20.5 (13.1) cm/s and 4.23 (2.80) cm, respectively, P < 0.05). A reversed pattern of systolic blood flow velocity was found in three patients with severe anterior wall and septal hypertrophy. During diastole there was prolongation of the diastolic acceleration (203 (53) ms v 110 (60) ms in controls, P < 0.05) and deceleration times (487 (200) ms v 210 (90) ms in controls, P < 0.05). There was no significant difference between those with and without symptoms or a left ventricular outflow tract gradient.

CONCLUSIONS

Patients with hypertrophic cardiomyopathy have abnormal systolic and diastolic coronary flow profiles at rest when measured by transthoracic echocardiography.

Radial versus femoral approach for diagnostic coronary angiography in stable angina pectoris

We compared coronary angiography of the radial artery using 6Fr catheters in 116 patients with that of the femoral artery in 100 case controls. We showed that transradial coronary angiography offers a useful alternative to the femoral route and can be performed without resorting to 5Fr catheters.

Transthoracic echocardiographic measurement of coronary blood flow and reserve

The objectives of this study were to evaluate the use of high-frequency (5 MHz) transthoracic echocardiography for the noninvasive measurement of coronary blood flow and to test its ability to detect small changes in blood flow that may accompany pharmacologic intervention. High-frequency (5 MHz) transthoracic echocardiography was performed on the distal segment of the left anterior descending coronary artery of 32 consecutive patients (23 men and nine women; mean age 60 +/- 10 years) before and after the administration of 0.4 mg sublingual nitroglycerin. The results were compared with those of 10 patients (eight men and two women; mean age 59 +/- 6 years) in whom the ungrafted left internal mammary artery was studied. Doppler velocity profiles of the left anterior descending coronary artery were detected in 18 (56%) of the 32 Study patients. Left anterior descending coronary artery diameter and blood flow were measured in 14 patients (44%). There was no significant difference in blood flow between the left anterior descending artery (74 +/- 35 ml/min) and the internal mammary artery (52 +/- 25 ml/min). After administration of nitroglycerin, there was a 24% decrease in coronary blood flow from 74 +/- 35 ml/min to 56 +/- 30 ml/min (p < 0.05). This study suggests that high frequency transthoracic echocardiography may allow noninvasive identification of the left anterior descending coronary artery and detection of small changes in blood flow that accompany pharmacologic and mechanical intervention.

Midterm results of mitral valve repair with the Sculptor annuloplasty ring

BACKGROUND

The partly flexible Sculptor ring is more physiologic than the rigid Carpentier-Edwards ring and may improve outcome.

METHODS

We studied 221 consecutive patients who underwent mitral valve repair for mitral regurgitation. The Sculptor ring was randomly implanted in 30 patients (Sculptor ring group) and the Carpentier-Edwards ring in 36 patients (Carpentier-Edwards ring control group) from 1993 to 1994. Before 1993, 155 patients received the Carpentier-Edwards ring (Carpentier-Edwards ring historical group). Baseline group characteristics were similar.

RESULTS

Thirty-day mortality in the Sculptor ring, Carpentier-Edwards ring control, and Carpentier-Edwards ring historical groups was 0.0% versus 2.8% versus 3.2% (p = 0.61), respectively. At 18 months, survival was 86% +/- 6% versus 88% +/- 7% versus 90% +/- 3% (p = 0.89), and freedom from complications was 100% +/- 0% versus 100% +/- 0% versus 98% +/- 1% (p = 0.51) for endocarditis, 90% +/- 6% versus 94% +/- 4% versus 96% +/- 2% (p = 0.47) for severe mitral regurgitation, 93% +/- 5% versus 91% +/- 5% versus 92% +/- 2% (p = 0.91) for thromboembolism, and 77% +/- 8% versus 80% +/- 7% versus 82% +/- 3% (p = 0.49) for myocardial failure, respectively.

CONCLUSIONS

The Sculptor ring is a safe alternative to the prosthetic annuloplasty rings in current use. The benefits of its physiologic design are either clinically insignificant or undetectable with a small sample size.

Echocardiography in mitral valve repair for mitral regurgitation: the surgeon's needs

Mitral valve repair has become the operation of choice for mitral regurgitation. It is often technically more demanding than valve replacement. The role of echocardiography has now extended beyond the identification of severe mitral regurgitation that would benefit from surgical correction. It helps the surgeon to assess valve reparability preoperatively, to assess the need for valve surgery in equivocal cases of ischemic mitral regurgitation, to plan the operation, and to assess valve function after repair. This article aims to discuss the role of echocardiography in providing the information needed by the surgeon for successful mitral valve repair. The echocardiographer must understand the surgeon's needs, while surgeons should understand both the benefits and limitations of echocardiography.

Superiority of mitral valve repair in surgery for degenerative mitral regurgitation

OBJECTIVES

We aimed to assess the influence of type of operation on outcome in degenerative mitral regurgitation.

METHODS

We compared outcomes in 278 consecutive patients who underwent mitral valve repair (167 patients), replacement with subvalvular preservation (22 patients) and without subvalvular preservation (89 patients) for degenerative mitral regurgitation.

RESULTS

There was a trend towards lower mortality with repair and replacement with subvalvular preservation compared to replacement without subvalvular preservation. Thirty-day mortality was 1.2% vs 0.0% vs 4.7% (ns) respectively. Six-year survival was, respectively, 67.8 +/- 7.4% (P = 0.088) vs 80.8 +/- 11.0% (P = 0.25) vs 63.3 +/- 5.9% for all-cause death, 78.5 +/- 6.8% (P = 0.063) vs 95.5 +/- 4.4% (P = 0.092) vs 67.6 +/- 5.9% for all complication-related death and 80.5 +/- 6.9% (P = 0.076) vs 100.0 +/- 0.0% (P = 0.045) vs 72.8 +/- 5.8% for complication-related death due to myocardial failure. Multivariate analysis confirmed independent beneficial effects from repair compared to replacement without subvalvular preservation on complication-related death (hazard ratio 0.42, P = 0.010) and death from myocardial failure (hazard ratio 0.40, P = 0.014), and from repair compared to mechanical replacement on thromboembolism (hazard ratio 0.45, P = 0.029) and anticoagulation-related haemorrhage (hazard ratio 0.19, P = 0.026).

CONCLUSIONS

Mitral valve repair is superior to replacement. The greatest survival advantage is in reduced mortality from myocardial failure. Repair should be the operation of choice for degenerative mitral regurgitation.

Assessment of apical hypertrophic cardiomyopathy using transoesophageal echocardiography

Two-dimensional echocardiography is the method of choice for imaging and diagnosis in patients with hypertrophic cardiomyopathy. However, ultrasound examination of the left ventricular apex by transthoracic echocardiography is often inadequate so that hypertrophy localised to this region may be missed. The purpose of this study was to evaluate the use of multiplane transoesophageal echocardiography in the diagnosis and assessment of apical hypertrophic cardiomyopathy. Six patients with apical hypertrophic cardiomyopathy underwent transthoracic and multiple transoesophageal echocardiography. Assessment of the proximal left ventricle was possible in all patients by both techniques and normal wall thickness measurements were obtained. Assessment of the distal left ventricle by multiple transesophageal echococardiography revealed hypertrophy of the apex (range 1.7-2.9 cm) and less marked hypertrophy of the distal segments of the left ventricle in all 6 patients (1.4-2.2 cm). Examination of the papillary muscles was also possible and hypertrophy was detected in 2 patients. By transthoracic echocardiography, hypertrophy was detected in the distal left ventricle of 5 patients and values were less than those obtained by multiplane transoesophageal echocardiography. No papillary muscle hypertrophy was seen. The apical segment was imaged in only 4 patients and maximum thicknesses of the apical segment were greater by multiple transoesophageal echocardiographic examination than by transthoracic echocardiography (mean 2.25 +/- 0.4 and 1.97 +/- 0.3 cm, respectively). We conclude that apical hypertrophic cardiomyopathy may be difficult to diagnose using transthoracic echocardiography because of inconsistent imaging of the apical segment. The distribution of hypertrophy may be inappropriately assigned and the severity of wall thickening underestimated. Multiplane transoesophageal echocardiography allows high resolution imaging of all segments of the left ventricle, particularly the apex.

Mitral valve surgery in the elderly

BACKGROUND AND AIMS OF THE STUDY

Previous studies have shown that outcome from mitral valve surgery is poorer in the elderly. However, such studies did not distinguish between age itself, age-associated factors and interactions between age and other factors. We aimed to examine the relative influences of age and these other factors on outcome.

METHODS

We compared outcomes from mitral valve repair or replacement in 190 elderly (> or = 70 years) and 424 younger (< 70 years) consecutive adult patients.

RESULTS

At baseline, the elderly had more (p > 0.05) degenerative mitral regurgitation, coronary artery disease, left ventricular impairment, New York Heart Association (NYHA) class III or IV symptoms, bioprosthetic replacement and mitral valve repair. Operative mortality rate was low both in elderly (7/190 patients, 3.7%) and younger patients (15/424 patients, 3.5%, NS). Seven-year survival was poorer in the elderly with respect to overall survival, (49 +/- 6% vs. 72 +/- 3%, p = 0.0001), freedom from complications-related death (57 +/- 7% vs. 79 +/- 3%, p = 0.001), from death due to myocardial failure (66 +/- 6% vs. 86 +/- 3%, p < 0.0001) and from overt myocardial failure (44 +/- 7% vs. 74 +/- 3%, p = 0.0001). Multivariate analysis showed better survival with younger age, mitral valve repair, better preoperative NYHA class and better left ventricular function. However, 7-year freedom from complications-related death was excellent and similar in both elderly (90 +/- 7%) and younger (93 +/- 3%, NS) patients who underwent surgery early while in NYHA class I or II with left ventricular ejection fraction > 40%.

CONCLUSIONS

Late surgery contributes far more than age itself to poor outcome from mitral valve surgery in the elderly. If surgery is performed early and repair preferred to replacement whenever feasible, medium-term results are excellent in both young and old.

Importance of subvalvular preservation and early operation in mitral valve surgery

BACKGROUND

Mitral valve replacement (MVR) has a high mortality and morbidity. It has been suggested that preservation of the subvalvular apparatus and more optimal timing of surgery might improve outcome.

METHODS AND RESULTS

We performed a retrospective study of 612 consecutive patients who underwent mitral valve repair or replacement: 226 patients had repair, 68 had replacement with subvalvular preservation (MVR/SVP), and 318 had replacement without subvalvular preservation (MVR/NoSVP). Baseline characteristics were most unfavorable in the repair group with respect to age (P = .002) and in the repair and MVR/SVP groups with respect to NYHA functional class and left ventricular function (P = .044). Thirty-day mortality was lower in the repair (1.8%, P = .046) and MVR/SVP (1.5%. P = NS) groups than the MVR/NoSVP group (5.0%). Overall survival at 7 years was better in the repair (71.2 +/- 5.6%. P = .022) and MVR/SVP (66.2 +/- 12.4%, P = .017) groups than the MVR/NoSVP group (63.5 +/- 3.4%). Myocardial failure caused 66 of 107 complication-related deaths. Multivariate analysis confirmed independent beneficial effects of repair on 30-day mortality (odds ratio, 0.27, P < .05) and of repair and MVR/SVP on overall mortality (hazard ratios, 0.43, P < .001 and 0.40, P < .05, respectively) and complication-related death hazard ratios, 0.38, P < .001 and 0.35, P < .05, respectively). Preoperative NYHA class III or IV symptoms and left ventricular impairment were independent risk factors for death and myocardial failure.

CONCLUSIONS

Mitral valve repair is superior to replacement. If repair is not feasible, the subvalvular apparatus should be preserved. Early surgery before the development of severe symptoms and demonstrable left ventricular impairment is also needed to optimize outcome.

Changing from intensive anticoagulation to treatment with aspirin alone for coronary stents: the experience of one centre in the United Kingdom

OBJECTIVE

To investigate whether an elective change in the anticoagulation protocol for patients with coronary stents affected clinical outcomes and length of hospital stay.

DESIGN

Retrospective observational study of a consecutive series of patients treated with coronary stents over an 18 month period from April 1994 to October 1995.

BACKGROUND

Intensive anticoagulation regimens are used in many UK centres to reduce the risk of coronary stent thrombosis. Recent data have called into question the necessity for full anticoagulation and favourable results have been reported with antiplatelet agents alone. The results from a tertiary referral centre were investigated during a period where an elective change in policy was made: an initial 70 patients were treated intensively with intravenous heparin and with warfarin and aspirin; subsequently 94 were treated with aspirin and deployment of a high pressure balloon only.

METHODS

Review of case notes, angiograms, and a database of intervention procedures and telephone interview. Classic epidemiological techniques, as well as linear regression and logistic regression, were used to model the outcomes of major procedural complications and length of hospital stay.

PATIENTS

164 patients treated with 196 coronary stents.

RESULTS

There were 22 (13.4%) major complications (coronary bypass grafting 11, subacute thrombosis 6, tamponade 2, myocardial infarction 1, death 2). With logistic regression, the risk of major complication was shown not to be affected by anticoagulation (relative risk (RR) 1.03; P = 0.97). Significant determinants of risk included acute vessel closure as an indication for stenting (RR = 80.6; P < 0.001) and sex (male: female RR = 0.19; P = 0.02). The median length of stay (LOS) was 5 days (1-45). Use of a linear regression model showed that anticoagulation added 4.5 days and a major complication added a further 4.5 days to a baseline length of stay of 3.2 days (R2 = 0.32; P < 0.001).

CONCLUSION

This is a report of coronary stenting as part of usual clinical practice in one British tertiary referral centre. In this experience, treatment with aspirin alone is probably as safe as intensive anticoagulation, and has the benefit of reducing length of stay by more than 50% to 3.2 days in an uncomplicated case.