[Analysis of mitral annulus excursion with tissue Doppler echocardiography (tissue Doppler echocardiography = TDE). Noninvasive assessment of left ventricular, diastolic dysfunction]

BACKGROUND

Mitral inflow velocity, deceleration time, and isovolumic relaxation time recorded by Doppler echocardiography have been widely used to evaluate left ventricular diastolic function but are affected by age, heart rate, loading conditions, and other factors. The diastolic mitral anulus velocity assessed by tissue Doppler echocardiography (TDE) was suggested to provide additional information about LV relaxation less affected by filling pressures.

AIM OF THE STUDY

This study was designed to assess the clinical utility of mitral anulus velocity in the evaluation of left ventricular diastolic function.

PATIENTS AND METHODS

Three groups of patients with a systolic ejection fraction > 45% were separated: 10 normal volunteers (60 +/- 10 y, CON group), 15 asymptomatic patients with known coronary artery disease (60 +/- 11 y, CAD group) and 15 patients with long-term arterial hypertension and heart failure symptoms (58 +/- 9 y, HYP group). The mitral inflow profile (E, A, E/A) was measured by pulsed Doppler, and the deceleration time (DT) and the isovolumic relaxation period (IVRT) were calculated. Systolic, early, and late diastolic velocities of the septal mitral anulus (ST, ET, AT, ET/AT) were assessed by pulsed TDE. All study subjects had invasive measurements of left ventricular end diastolic filling pressures during left heart catheterization.

RESULTS

In the AH group, ET (6.9 +/- 4.8 cm/s) and ET/AT (0.71 +/- 0.28) were reduced compared to the CON group (11.7 +/- 4.7 cm/s and 1.11 +/- 0.36, p < 0.05, respectively) and the CAD group (8.9 +/- 5.4 cm/s and 0.85 +/- 0.26, respectively, p = ns). The groups did not differ with respect to the mitral E/A ratio, the deceleration time and the isovolumic relaxation time. LVED in the HYP group (16 +/- 8 mm Hg) was elevated compared to the CON group (8 +/- 3, p < 0.05) and the CAD group (12 +/- 6 mm Hg, p = ns). No correlation was found between ET and LVED (r = 0.26). When the combination of mitral E/A ratio > 1 with LVED > or = 15 mm Hg was classified as pseudonormalization, the pseudonormalization could be identified by a peak early diastolic mitral anulus velocity (ET) < 7 cm/s and an ET/AT ratio < 1 with a sensitivity of 77% and a specificity of 88%.

CONCLUSIONS

The early diastolic mitral anulus velocity assessed by TDE (ET) is a preload-independent index of LV relaxation. TDE permits the detection of diastolic dysfunction in patients with a pseudonormal mitral inflow and elevated filling pressures.

Augmented alpha-adrenergic constriction of atherosclerotic human coronary arteries

BACKGROUND

Although adrenergic activation plays a major role in the initiation of experimental myocardial ischemia, the significance of alpha-adrenergic coronary constriction in humans has been questioned. The present study assessed the impact of selective alpha-adrenergic receptor activation in patients with normal or atherosclerotic coronary arteries.

METHODS AND RESULTS

In 39 patients, coronary blood flow (CBF, mL/min) was determined from combined angiography and Doppler measurements. In 8 patients with normal coronary arteries (group 1) and 9 with single coronary artery stenosis (group 2), doses of 1, 2.5, 5, and 10 mg IC of the alpha1-agonist methoxamine (M) were injected. Identical doses of the alpha2-agonist BHT933 (B) were injected in 8 patients with normal coronary arteries (group 3) and 8 with single stenosis (group 4). In 6 additional patients with single stenosis (group 5), aortocoronary sinus lactate differences were measured in response to M and B. CBF remained unchanged in group 1. In contrast, CBF was decreased dose-dependently in group 2, with a maximum at 10 mg M (39.0+/-9.4 versus 15.2+/-7.0). In groups 3 and 4, CBF was also decreased dose-dependently, with a maximum at 10 mg B (63.3+/-24.8 versus 49. 1+/-27.9 and 41.5+/-19.0 versus 12.7+/-8.0, respectively). In group 5, there was more net lactate production with B than with M (-0. 34+/-0.11 versus -0.04+/-0.09 mmol/L).

CONCLUSIONS

In normal coronary arteries, alpha1-adrenergic activation does not reduce CBF, whereas alpha2-adrenergic activation reduces CBF by microvascular constriction. Both alpha1- and alpha2-adrenergic epicardial and microvascular constriction are augmented by atherosclerosis and can induce myocardial ischemia.

Improved high-frequency transthoracic flow velocity measurement in the left anterior descending coronary artery after intravenous peripheral injection of levovist

New ultrasonic technology allows noninvasive measurement of the flow in the distal left anterior descending coronary artery. The goal of this study was to validate transthoracic determination of coronary flow velocity with the intracoronary Doppler flow wire technique. In 20 patients with normal coronary arteries, 2 intracoronary and 2 comparative transthoracic Doppler measurements (TTDMs) of the average peak velocity (APV) and the mean systolic and diastolic velocities were performed. The diastolic/systolic ratio was calculated. Blood flow velocity was determined in the distal left anterior descending coronary artery with a Doppler guide wire. Color Doppler and subsequent pulsed wave Doppler readings in an optimal left lateral position were available within 1 hour after completion of the invasive examinations. TTDM were performed during continuous administration of 2.0 g of contrast agent. A modified apical view was obtained from the fourth or fifth intercostal space, and a high-frequency transducer was used (7 MHz for 2-dimensional and 6 MHz for color Doppler imaging; 3.5 MHz for pulsed wave Doppler readings). The Doppler flow signal quality was graded from I to III (I = no flow mapping obtainable, II = poor quality, III = Doppler signals with a well-defined outline). In 13 (65%) patients, 26 TTDMs revealed signal quality of grade III. APV was calculated to be within normal limits (APVecho = 19.96 +/- 7.62 cm/s vs APVinvasive = 20.77 +/- 7.87 cm/s). APVecho correlated well with APVinvasive (r = 0.85, y = 0.82x + 2.85, P <.001). The mean difference between APVecho and APVinvasive (Bias) was -0.81 +/- 4.23 cm/s. No correlation was found between invasive and noninvasive measurements of diastolic/systolic velocity ratios (P >.05). High-frequency TTDM provides reliable data on APV in the majority of patients. It has the potential to be introduced as a relevant screening test for follow-up of patients after interventional treatment.

The presence of infection-related antiphospholipid antibodies in infective endocarditis determines a major risk factor for embolic events

OBJECTIVES

The impact of infection-associated antiphospholipid antibodies (APA) on endothelial cell activation, blood coagulation and fibrinolysis was evaluated in patients with infective endocarditis with and without major embolic events.

BACKGROUND

An embolic event is a common and severe complication of infective endocarditis. Despite the fact that APAs are known to be associated with infectious diseases, their pathogenic role in infective endocarditis has not been clearly defined.

METHODS

The relationship among the occurrence of major embolic events, echocardiographic vegetation size, endothelial cell activation, thrombin generation, fibrinolysis and APA was examined in 91 patients with definite infective endocarditis, including 26 patients with embolic events and 65 control subjects without embolic events.

RESULTS

Overall, 14.3% of patients exhibited elevated APA levels. Embolic events occurred more frequently in patients with elevated levels of APA than in patients without (61.5% vs. 23.1%; p = 0.008). Patients with elevated levels of APA showed higher levels of prothrombin-fragment F1 +2 (p = 0.005), plasminogen-activator inhibitor 1 (p = 0.0002), von Willebrand factor (p = 0.002) and lower levels of activated protein C (p = 0.001) than patients with normal levels of APA. Thrombin generation and endothelial cell activation were both positively correlated with levels of APA. The occurrence of elevated APA levels was frequently associated with structural valve abnormalities (p = 0.01) and vegetations >1.3 cm (p = 0.002).

CONCLUSIONS

Infection-associated elevated APA levels in patients with infective endocarditis are related to endothelial cell activation, thrombin generation and impairment of fibrinolysis. This may contribute to the increased risk for major embolic events in these patients.

Chest pain after coronary interventional procedures. Incidence and pathophysiology

Chest pain following successful percutaneous coronary interventions is a common problem. Although the development of chest pain after coronary interventions may be of benign character, it is disturbing to patients, relatives and hospital staff. Such pain may be indicative of acute coronary artery closure, coronary artery spasm or myocardial infarction, but may also simply reflect local coronary artery trauma. The distinction between these causes of chest pain is crucial in selecting optimal care. Management of these patients may involve repeat coronary angiography and additional intervention. Commonly, repeat coronary angiography following percutaneous transluminal coronary angioplasty (PTCA) in patients with chest pain demonstrates widely patent lesion sites suggesting that the pain was due to coronary artery spasm, coronary arterial wall stretching or was of non-cardiac origin. As reported by the National Heart, Lung and Blood Institute PTCA Registry, 4.6% of patients after angioplasty have coronary occlusions, 4.8% suffer a myocardial infarction, and 4.2% have coronary spasm. The frequency of chest pain after new device coronary interventions (atherectomy and stenting) seems to be even higher. However, only the minority of patients with post-procedural chest pain have indeed an ischemic event. Therefore, the vast majority of patients have recurrent chest pain without any signs of ischemia. There is some evidence that non-ischemic chest pain after coronary interventions is more common after stent implantation as compared to PTCA (41% vs. 12%). This may be due to the continuous stretching of the arterial wall by the stent as the elastic recoil occurring after PTCA is minimized. In conclusion, chest pain after coronary interventional procedures may potentially be hazardous when due to myocardial ischemia. However, especially after coronary stent placement, cardiologists must consider "stretch pain" due to the overdilation and stretching of the artery caused by the stent in the differential diagnosis. Clinically, it is, therefore, important to recognize that in addition to ischemia-related chest pain other types of chest pain do exist with cardiac origin.

Can right-sided atrioventricular sequential pacing provide benefit for selected patients with severe congestive heart failure?

This study reports on the methods and results of applying right-sided atrioventricular (AV) pacing in 26 patients with advanced cardiomyopathy. Ten of these patients had ischemic cardiomyopathy. Of the 16 patients with nonischemic cardiomyopathy, 10 were idiopathic and 6 were due to secondary causes. The patients had a mean age of 56 +/- 12 years and a left ventricular ejection fraction of 26 +/- 11%. Two transvenous stimulation electrodes were temporarily placed in the high right atrium and right ventricle, respectively. A Swan Ganz catheter was positioned into the pulmonary artery to determine cardiac output by the thermodilution method and to measure the pressure in the pulmonary artery and right atrium. In addition, aortic pressure was measured through a catheter sheath via the right femoral artery. Systemic and pulmonary vascular resistance were calculated. Stimulation was performed in VVI and DDD pacing modes using different AV intervals (40, 80, 125, 150, 175, 200, and 250 msec). No increase of cardiac output was observed for the overall study cohort (p = 0.51). At VVI pacing, stroke volume significantly decreased from 66 +/- 20 mL to 53 +/- 13 mL (p < 0.01). We distinguished between responders who developed an increase of cardiac output of > 1 L/min (n = 12, 46%) and nonresponders (n = 14, 54%). Etiology of either ischemic or nonischemic cardiomyopathy for responders, as well as conduction disturbances (first-degree AV block, LBBB, RBBB), were equally distributed among both groups. Using an AV delay of 150 and 175 msec, responders to DDD pacing derived a significant increase in cardiac output. An AV delay of 150 msec produced both a significant increase of stroke volume and decrease of systemic vascular resistance. In 46% of patients with dilated cardiomyopathy of either ischemic or nonischemic origin, right-sided AV-sequential pacing brought about an improvement of left ventricular function in terms of enhanced cardiac output. We suggest individual testing in all patients with severe left ventricular dysfunction to find responders.

A prognostic computer model to individually predict post-procedural complications in interventional cardiology: the INTERVENT Project

AIMS

The purpose of this part of the INTERVENT project was (1) to redefine and individually predict post-procedural complications associated with coronary interventions, including alternative/adjunctive techniques to PTCA and (2) to employ the prognostic INTERVENT computer model to clarify the structural relationship between (pre)-procedural risk factors and post-procedural outcome.

METHODS AND RESULTS

In a multicentre study, 2500 data items of 455 consecutive patients (mean age: 61.1+/-8.3 years: 33-84 years) undergoing coronary interventions at three university centres were analysed. 80.4% of the patients were male, 16.7% had unstable angina, and 5.1%/10.1% acute/subacute myocardial infarction. There were multiple or multivessel stenoses in 16.0%, vessel bending >90 degrees in 14.5%, irregular vessel contours in 65.0%, moderate calcifications in 20.9%, moderate/severe vessel tortuosity in 53.2% and a diameter stenosis of 90%-99% in 44.4% of cases. The in-lab (out-of-lab) complications were: 0.4% (0.9%) death, 1.8% (0.2%) abrupt vessel closure with myocardial infarction and 5.5% (4.0) haemodynamic disorders.

CONCLUSION

Computer algorithms derived from artificial intelligence were able to predict the individual risk of these post-procedural complications with an accuracy of >95% and to explain the structural relationship between risk factors and post-procedural complications. The most important prognostic factors were: heart failure (NYHA class), use of adjunctive/alternative techniques (rotablation, atherectomy, laser), acute coronary ischaemia, pre-existent cardiac medication, stenosis length, stenosis morphology (calcification), gender, age, amount of contrast agent and smoker status. Pre-medication with aspirin or other cardiac medication had a beneficial effect. Techniques, such as laser angioplasty or atherectomy were predictors for post-procedural complications. Single predictors alone were not able to describe the individual outcome completely.

Stepwise intravascular ultrasound (IVUS) guidance of high-pressure coronary stenting does not result in an improved acute or long-term outcome: a randomized comparison to "final-look" IVUS assessment

The objective of this study was to evaluate the potential benefit of stepwise intravascular ultrasound (IVUS)-guided coronary stent deployment compared to angiographic stent implantation with final IVUS assessment only. Acute procedural success and 6-month angiographic follow-up were compared in both groups. Intravascular ultrasound was performed using a 20- or 30-MHz mechanically rotated catheter in 85 patients who were prospectively randomized to group A (n=42; IVUS-guided) and group B (n=43; angiography +/- final IVUS assessment). There was no difference in the number of stents implanted (1.5+/-0.9 stents/lesion in group A and 1.3+/-0.6 stents/lesion in group B), the duration of the procedure, or the amount of contrast medium used. Defined criteria of optimal stent deployment (stent apposition, stent symmetry, complete coverage of dissections, >90% in-stent lumen area/reference lumen area) were achieved in 54.2% in group A and 56.6% in group B (NS). Angiographic follow-up was 87.1% at 6+/-2 months, and clinical follow-up was 100% at 8+/-1 months. There was no significant difference in restenosis rate (33.3% vs. 34.9%) applying a binary >50% diameter stenosis criterion for both groups. There was no significant difference in minimal in-stent lumen area at both baseline (7.91+/-2.64 mm2 vs. 7.76+/-2.21 mm2) and follow-up (5.84+/-2 mm2 vs. 5.52+/-1.87 mm2). With regard to immediate procedural lumen gain and rate of restenosis, multiple IVUS examinations during the procedure showed no advantage compared to final IVUS assessment only.

Role of intravascular ultrasound imaging in identifying vulnerable plaques

A plaque that has a large lipid core and a thin fibrous cap may undergo rupture. Once it ruptures, it may lead to thrombus formation and subsequent vessel occlusion. To identify unstable plaques before they rupture is essential for clinical management and patient's prognosis. Intravascular ultrasound (IVUS) opens a new window for the assessment of plaque morphology to identify vulnerable plaques and plaque rupture. We examined 144 patients with angina and ischemic ECG changes using IVUS. Ruptured plaques, characterized by a plaque cavity and a tear on the thin fibrous cap, were identified in 31 patients (group A) of which 23/31 (74%) clinically presented as unstable angina. Plaque rupture was confirmed by injecting contrast medium filling the plaque cavity during IVUS examination. Of the patients without plaque rupture (group B, n = 108), only 19 (18%) had unstable angina. No significant differences between the 2 groups were found concerning the vessel and plaque areas (p > 0.05). The percent stenosis in group A (56.2 +/- 16.5%) was significantly lower than in group B (67.9 +/- 13.4%) (p < 0.001). Area of the plaque cavity in group A (4.1 +/- 3.2 mm2) was significantly larger than the echolucent zone in group B (1.32 +/- 0.79 mm2) (p < 0.001). The plaque cavity/plaque ratio in group A (38.5 +/- 17.1%) was larger than the echolucent area/plaque ratio in group B (11.2 +/- 8.9%) (p < 0.001). The thickness of the fibrous cap in group A (0.47 +/- 0.20 mm) was significantly thinner than that (0.96 +/- 0.94 mm) in group B (p < 0.001).

CONCLUSIONS

Plaques seem to be prone to rupture when the echolucent area is larger than 1 mm2, the echolucent area/plaque ratio greater than 20% and the fibrous cap thinner than 0.7 mm. IVUS has the capacity of identifying plaque rupture and vulnerable plaques. This may have potential influence on patients management and therapy.

[Shy-Drager syndrome: a rare cause of orthostatic hypotension]

HISTORY AND ADMISSION FINDINGS

A 71-year-old man was admitted because of treatment-resistant orthostatic hypotension of unknown aetiology. When aged 64 years he developed some impotence and later urinary incontinence and urinary frequency. At 68 years he noted vertigo on physical activity, and a year later he had signs of reversible cerebral ischaemia. At this point the Schellong test demonstrated vasovagal circulatory dysfunction. After his 70th birthday the unsteadiness on walking and standing got worse and he had recurrent syncopes. He was in a wheel-chair when hospitalized and even the unsteady walk he could maintain for only a few seconds.

INVESTIGATIONS

Plasma and urinary concentrations of catecholamines were at the lower limit of normal but failed to increase during orthostasis. Hormonal, cardiological and infectious causes of the orthostatic hypotension were excluded. Orthostatic tests after Schellong and with the tilting table showed orthostatic hypotension without increased sympathetic activity but hypertensive blood pressure levels during the recumbent period. Intravenous infusion of norepinephrine produced an excess rise in blood pressure (raised norepinephrine sensitivity). The recurrent urinary infection was shown to be due to a hypotonic bladder detrusor muscle. Neurological examination revealed cerebellar dysfunction, signs of pyramidal tract abnormality and sensory polyneuropathy. A Shy-Drager syndrome was diagnosed on the basis of the history, absent blood pressure rise and lack of catecholamine release during orthostasis with increased epinephrine sensitivity and characteristic neurological signs.

TREATMENT AND COURSE

Physiotherapy and elastic stockings with administration of mineralocorticoids as well as of one direct (norfenefrine) and one indirect (amezinium) sympathomimetic drug failed to improve adequately the abnormal orthostatic response. But on additional administration of an alpha 2-receptor antagonist (yohimbine) the patient was able to stand and walk for a few minutes, but the urinary incontinence and the other neurological signs remained treatment-resistant.

CONCLUSION

If orthostatic hypotension occurs together with neurological symptoms, a Shy-Drager syndrome should be taken into account.

Percutaneous transluminal therapy of occluded saphenous vein grafts: can the challenge be met with ultrasound thrombolysis?

BACKGROUND

Percutaneous transluminal treatment of a thrombotic vein graft yields poor results. We have previously reported our experience with transluminal percutaneous coronary ultrasound thrombolysis (CUT) in the setting of acute myocardial infarction (AMI). This report describes the first experience with ultrasound thrombolysis in thrombus-rich lesions in saphenous vein grafts (SVGs), most of which were occluded.

METHODS AND RESULTS

The patients (n=20) were mostly male (85%), aged 64+/-4 years old. The presenting symptom was AMI in 2 patients (10%) and unstable angina in the rest. Fifteen patients (75%) had totally occluded SVGs. The median age of clots was 6 days (range, 0 to 100 days). The ultrasound thrombolysis device has a 1.6-mm-long tip and fits into a 7F guiding catheter over a 0.014-in guidewire in a "rapid-exchange" system. CUT (41 kHz, 18 W, </=6 minutes) led to device success in 14 (70%) of the patients and residual stenosis of 65+/-28%. Procedural success was obtained in 13 (65%) of the patients, with a final residual stenosis of 5+/-8%. There was a low rate of device-related adverse events: 1 patient (5%) had a non-Q-wave myocardial infarction, and distal embolization was noted in 1 patient (5%). Adjunct PTCA or stenting was used in all patients. There were no serious adverse events during hospitalization.

CONCLUSIONS

Ultrasound thrombolysis in thrombus-rich lesions in SVGs offers a very promising therapeutic option.

Nonischemic chest pain induced by coronary interventions: a prospective study comparing coronary angioplasty and stent implantation

BACKGROUND

Chest pain frequently occurs without any signs of ischemia within the first 24 hours after coronary interventions. To test the hypothesis that this pain may be due to local vessel injury ("stretch pain"), we performed a prospective study enrolling patients after PTCA, stent implantation, or diagnostic coronary angiography alone.

METHODS AND RESULTS

A total of 145 patients after coronary angiography were evaluated by a validated questionnaire for quantifying postinterventional chest pain within 24 hours. To detect myocardial ischemia, all patients were evaluated with a 12-lead ECG and cardiac isoenzymes immediately after the procedure and the morning after. After stent implantation, 21 of the 51 patients (41.2%) developed chest pain, compared with 4 of the 33 patients (12.1%) undergoing PTCA and 6 of the 61 patients (9.8%) with a diagnostic angiography (P<0.001). Of these 31 patients who developed chest pain, only 3 (9.7%) felt that the pain was similar to previously experienced angina pectoris. The minimal lumen diameter after intervention was significantly larger in the stent group than in the PTCA group (3.14+/-0.75 versus 1.95+/-0.67 mm; P<0. 001). No patient had changes in the ECG compared with before intervention, but 3 patients after stent implantation had a rise in cardiac isoenzymes. No other major adverse cardiac events occurred until discharge.

CONCLUSIONS

Nonischemic chest pain develops in almost half of all patients undergoing stent implantation and seems to be related to vessel overexpansion caused by the stent in the diseased vessel segment.

Standardized guidelines for the interpretation of dobutamine echocardiography reduce interinstitutional variance in interpretation

Subjective interpretation of dobutamine echocardiograms provides only moderate interinstitutional observer agreement if nonunified data acquisition and assessment criteria are applied. The present study was undertaken to evaluate parameters associated with low interinstitutional observer agreement in the interpretation of dobutamine echocardiograms and to analyze whether standardized interpretation criteria improve interinstitutional observer agreement. One hundred fifty dobutamine echocardiograms (dobutamine up to 40 microg/kg/min body weight and atropine up to 1 mg) were evaluated at 5 centers. Clinical, procedural, and echocardiographic parameters were included in the analysis of variables with significant impact on interinstitutional agreement. Standardized interpretative criteria were established, and 90 dobutamine echocardiograms were reanalyzed by 3 observers using a standardized image display. Multivariate analysis demonstrated low image quality (odds ratio [OR] 0.19, 95% confidence interval [CI] 0.08 to 0.45, p=0.0002), low severity of induced wall motion abnormality (OR 0.17, 95% CI 0.07 to 0.40, p <0.0001), and a low peak rate-pressure product (OR 0.93, 95% CI 0.43 to 2.27, p=0.0382) to result in a low interinstitutional agreement. Standardization of image display in cine loop format and of dobutamine stress echo interpretation criteria resulted in improvement in test result categorization as normal or abnormal, with a kappa value of 0.50, compared with 0.39 using the original subjective interpretation. In conclusion, image quality, the severity of induced wall motion abnormalities, and the obtained rate-pressure product have a significant impact on the interpretation homogeneity of dobutamine echocardiograms. Standardization of image display in cine loop format and of reading criteria results in improved interinstitutional agreement in interpretation of stress echocardiograms.

Coronary-artery stenting compared with balloon angioplasty for restenosis after initial balloon angioplasty. Restenosis Stent Study Group

BACKGROUND

Intracoronary stenting reduces the rate of restenosis after angioplasty in patients with new coronary lesions. We conducted a prospective, randomized, multicenter study to determine whether intracoronary stenting, as compared with standard balloon angioplasty, reduces the recurrence of luminal narrowing in restenotic lesions.

METHODS

A total of 383 patients who had undergone at least one balloon angioplasty and who had clinical and angiographic evidence of restenosis after the procedure were randomly assigned to undergo standard balloon angioplasty (192 patients) or intracoronary stenting with a Palmaz-Schatz stent (191 patients). The primary end point was angiographic evidence of restenosis (defined as stenosis of more than 50 percent of the luminal diameter) at six months. The secondary end points were death, Q-wave myocardial infarction, bypass surgery, and revascularization of the target vessel.

RESULTS

The rate of restenosis was significantly higher in the angioplasty group than in the stent group (32 percent as compared with 18 percent, P= 0.03). Revascularization of the target vessel at six months was required in 27 percent of the angioplasty group but in only 10 percent of the stent group (P=0.001). This difference resulted from a smaller mean (+/-SD) minimal luminal diameter in the angioplasty group (1.85+/-0.56 mm) than in the stent group (2.04+/-0.66 mm), with a mean difference of 0.19 mm (P=0.01) at follow-up. Subacute thrombosis occurred in 0.6 percent of the angioplasty group and in 3.9 percent of the stent group. The rate of event-free survival at 250 days was 72 percent in the angioplasty group and 84 percent in the stent group (P=0.04).

CONCLUSIONS

Elective coronary stenting was effective in the treatment of restenosis after balloon angioplasty. Stenting resulted in a lower rate of recurrent stenosis despite a higher incidence of subacute thrombosis.

Electron-beam CT in the noninvasive assessment of coronary stent patency

RATIONALE AND OBJECTIVES

Coronary artery stents reduce the rate of restenosis in patients who have undergone balloon angioplasty; therefore, the implantation of coronary stents represents an important method in the treatment of coronary stenoses. The authors' purpose was to investigate the usefulness of electron-beam computed tomography (CT) as a noninvasive means of assessing the patency of coronary artery stents in patients who had undergone balloon angioplasty and stent placement.

MATERIALS AND METHODS

Electron-beam CT was used to assess stent patency in 177 patients with 285 stents. Contrast material-enhanced multisection flow studies were performed, and the images were evaluated by three investigators and compared with the findings of coronary angiography.

RESULTS

Cine loop evaluations and time-attenuation curve analysis led to the correct diagnosis in 167 (94.3%) patients, as confirmed with coronary angiography. Stenoses had occurred in 18 of the 194 vessels with stents, and 14 of these were detected with electron-beam CT.

CONCLUSION

Electron-beam CT appears to be a valuable imaging modality in the noninvasive assessment of stent patency in coronary arteries.

[Improved structure identification with tissue Doppler echocardiography]

Tissue Doppler echocardiography (TDE) has been shown to be of particular value in patients with impaired myocardial function. Recently, the technique was successfully employed to localize the ventricular insertion of accessory atrioventricular pathways. The identification of abnormal cardiac structures is coming up now as a new field of clinical interest. The purpose of this study was to differentiate anomalous cardiac and aortic from native structures by physical properties of tissue motion using transesophageal TDE. Characteristic motion patterns of anomalous structures have not been described in detail and tissue Doppler findings have not been associated with clinical features up to now. Forty consecutive patients were included after anomalous cardiac or vascular structures had been detected by conventional transesophageal echocardiography (TEE). A control group consisted of 20 subjects. Rapidity of diagnosis in anomalous structures was divided into 3 categories, and TDE signals were related to particular pathology by a blinded, 2nd observer. Three different motion patterns could be defined: incoherent motion due to free oscillation of an anomalous structure which is independent of the surrounding tissue (Figure 1b); coherent motion with a phase difference meaning that motion depends on the motion of the surrounding tissue but is out of phase (Figure 2); concordant motion showing no difference in direction, velocity, or phase of motion compared with the surrounding tissue. Incoherent motion was present in endocarditic vegetations, 4th degree aortic plaques, Chiari network, valvular prolapse, intracavitary tumors, and freely oscillating thrombi as well as in normal valve leaflets and papillary muscles. Especially if endocarditic vegetations are present its incoherent motion facilitates to recognize these small structures. The colorcode of this motion pattern demarcates the vegetation reliably from the surrounding tissue (Figure 1b). Within 15 seconds vegetations could be detected in 9 (82%) vs 2 (18%) patients employing only conventional imaging. Using conventional echocardiographic approaches detection of vegetations is frequently hindered by their small size and minor echo intensity (Figure 1a). In contrast, size and echo intensity do not affect the tissue Doppler signal. Normal papillary muscles and distal portions of the mitral and tricuspid valves were demonstrated to regularly meet the criterion of incoherent tissue motion in the control group. In part, this was also observed with respect to the aortic and pulmonary valves. In valvular tissue incoherent motion was caused by passive floating, whereas papillary muscles show an active inverse motion for short time intervals. Nevertheless, physiologic incoherent motion did not lead to any false differential diagnosis. The phase difference of coherent motion results from damped oscillation. This phenomenon was visualized by tissue Doppler M-mode in 5 thrombi of the left atrial appendage (LAA) (100%) and in 1 ventricular thrombus (50% of all clots). Concordant motion was shown in 3rd degree aortic plaques and postrheumatic and calcified vegetations. These structures were found to be completely embedded or closely attached, so that their passive motion corresponded to the motion of the surrounding regular tissue. Detection and assessment of anomalous structures are based on their motion patterns which can be synchronous or asynchronous in comparison with the surrounding tissue. Another goal of this investigation was to test if the sensitivity of TEE to spontaneous echo contrast can be improved using TDE. In 21 patients presenting with left atrial dilation (left atrial diameter > 44 mm) due to mitral stenosis (n = 8), mitral regurge (n = 5), arterial hypertension (n = 5) and multiple valvular disease (n = 3) fundamental multiplane TEE and transesophageal TDE were performed with standardized gain setting. The control group consisted of 20 randomized individuals with normal left

[Management of coronary perforation after percutaneous balloon angioplasty with a new membrane stent]

A 59 year old patient underwent percutaneous transluminal coronary angioplasty of a de novo stenosis of the proximal right coronary artery. Vessel perforation occurred after balloon angioplasty and was successfully treated by implantation of a new stent graft, which completely covered the perforation without residual leakage. Emergency coronary surgery could, thus, be avoided.

[Digital archiving of imaged heart catheter studies on CD-R. Detection of irreversible CD damage]

The digital archiving has great advantages compared to the standard 35-mm X-ray cinefilm documentation. The data are immediately available and quantitative coronary angiography possible. In addition the technical progress is enhancing the availability of data. The loss of films is nearly eliminated, as only copies of the digital archive data are delivered. In addition a big advantage concerning pollution is present, when CD Rs are used. We report about the damage of CD Rs after 89, 162, 181 and 252 days when they were stored in polypropylene material containing envelopes. The damaged CD Rs all belonged to the provider Verbatim, whereas CD Rs of the provider Rank Xerox or Kodak were never damaged. In contrary to the Verbatim company, Rank Xerox gave written confirmation for 10-year storage and a written confirmation, that the storage in the polypropylene envelopes is possible. Mechanical, thermal damage and damage by humidity have to be discussed as well as chemical interactions of the CD Rs surface with the polypropylene material. As the digital storage for X-ray images has to be provided for 10 years in Germany, it is concluded, that the storage in polypropylene envelopes has to be avoided, when a written confirmation by the company is not given. These observations should stimulate to better control and analyze the real storage availabilities of digital data and provide in the future other media than CD R for long-term archiving.

[Asynchrony of ventricular contraction and relaxation--pathophysiologically recognized phenomenon, now can be clinically assessed]

When regional myocardial dysfunction is present, the physiological pattern of ventricular filling and contraction is impaired. During acute coronary occlusion, characteristic changes are observed in the ischemic myocardial segment: the amplitude of the systolic wall thickening is reduced (hypokinesia), then virtually absent (akinesia) and finally replaced by a paradoxical outward motion (dyskinesia). The maximum amplitude is reached in early diastole ("post-ejection thickening"). Since hyperkinesis develops in the normal region, the ischemic and the normal region contract asynchronously. Experimentally left ventricular asynchrony can be detected by means of subendo- and subepicardially implanted ultrasonic crystals ("sonomicrometry") or by the analysis of the phase difference of the first Fourier harmonic of dysfunctional versus control myocardial wall motion. In the clinical setting, digitized cineventriculography, radionuclide angiography and digitized M-mode echocardiography were used to assess left ventricular asynchrony in patients with coronary artery disease and hypertrophic cardiomyopathy. However, these imaging modalities are time-consuming and require complicated off-line analysis. Tissue Doppler echocardiography (TDE) is a new ultrasound modality that is based on color Doppler principles and allows for quantification of myocardial wall motion velocity by detection of consecutive phase shifts of the ultrasound signal reflected from the myocardium. The Doppler signals are displayed as a color or pulsed Doppler image by rejecting low-amplitude echoes from the blood pool due to changes in thresholding and filtering algorithms. In addition, the ability to measure low velocity is improved in the TDE system so that the lowest measurable velocity is 0.2 cm/s, a velocity level associated with cardiac tissue motion (Table 1). Due to its high temporal and spatial resolution, TDE provides valuable information on regional myocardial wall motion during different intervals of the cardiac cycle. In healthy subjects, patients with coronary artery disease and patients with hypertrophic cardiomyopathy, tissue Doppler echocardiography was used to assess myocardial synchrony/asynchrony on a 2-fold temporal and spatial analysis. Peak myocardial velocities in different myocardial regions were detected during rapid ejection, isovolumic relaxation, rapid filling and atrial contraction (Figure 1). In the apical view, during the isovolumic relaxation time (IVRT) healthy subjects showed slow, synchronous outward motion of the septum and the lateral wall with homogeneous color-encoding (blue/green, Figure 2). Analysis of peak velocities revealed low, negative velocities in both the septum and the lateral wall (Figure 3). In patients with a significant luminal narrowing of the LAD myocardial asynchrony was detected during the isovolumic relaxation period: while the septum was moving inwards (red color-encoding with low, positive velocities), the lateral wall was moving outwards (blue/green encoding, low, negative velocities). A representative example of a patient with CAD is given in Figure 4. The M-mode analysis of the abnormally contracting interventricular septum reveals positive peak tissue velocities during the isovolumic relaxation period (Figure 5). In hypertrophic cardiomyopathy, TDE was able to detect an abnormal inward motion of the interventricular septum during IVRT and a delay in the onset of rapid filling (Figure 6). Thus, tissue Doppler echocardiography is a feasible method for the on-line detection of myocardial asynchrony. Sensitivity and specificity of the findings have to be explored in further, prospectively randomized trials.

[New imaging methods for visualizing coronary arteries]

Techniques in the field of coronary artery imaging can be divided into two groups: invasive and non-invasive methods. Apart from the conventional coronary artery angiography, invasive methods include intracoronary ultrasound, intracoronary angioscopy, and optical coherence tomography. Non-invasive methods include magnetic resonance tomography, synchrotron-coronary angiography, and electron beam computed tomography. In the late 1980s, intracoronary ultrasound has come into clinical practice. It offers a real-time, cross-sectional image of the coronary artery in high resolution. Coronary arteries enlarge in the presence of atherosclerotic plaque formation in order to compensate for luminal narrowing caused by plaque formation (remodeling). With coronary angiography, the plaque formation cannot be detected until a lumen reduction of about 40-45%. With intravascular ultrasound, the early stages of atherosclerosis can clearly be demonstrated. In combination with the intracoronary Doppler technique, syndrome X can be differentiated. Another important role of intracoronary ultrasound in the diagnosis of coronary artery disease is to guide coronary interventions and to assess the result of coronary interventions especially to evaluate the result of stent implantation. Due to the clinical use of intracoronary ultrasound and the guidance of high pressure stent implantation, the incidence of acute stent thrombosis has decreased to about 1%. Coronary angioscopy portrays the surface of the vessel lumen. It is helpful to identify the mural thrombus especially to differentiate fresh and chronic thrombus formation. Magnetic resonance tomography is able to image the coronary arterial contour of the proximal segment. With today's gating technique, it is possible to portray the whole coronary tree and avoid disturbances resulting from the heart beat and respiration. Electron beam computed tomography is a very promising technique in screening for coronary artery disease. It is a very sensitive method to identify coronary calcification and, thus, to detect atherosclerotic plaque. Studies have shown that the presence of calcification almost invariably indicates the presence of coronary artery disease and that the absence of calcification can nearly rule out significant coronary artery disease. Moreover, a close correlation exists between the amount of calcification and the severity of coronary artery disease. Additionally, in combination with contrast injection, coronary artery perfusion can be evaluated. This is important to assess the conductance of coronary stent and bypass graft.

[Arguments against conventional balloon dilatation of recurrences within the stent]

Today, stent restenosis is the major limitation of coronary stent implantation. Despite several prospective randomized trials, which documented significantly lower restenosis rates after stenting compared to conventional balloon angioplasty for the treatment of de-novo stenoses, restenotic lesions, bypass graft stenoses and symptomatic dissections, in daily clinical practice restenosis rates after coronary stenting are reported between 18% and 78% depending on the lesions treated. Interventional treatment options for symptomatic stent restenosis include repeat balloon angioplasty, a combination of ablative approaches (rotablation, laser angioplasty, directional atherectomy) with balloon angioplasty, and stent-in-stent (sandwich technique) placement. Long-term success for the treatment of focal (< or = 10 mm) stent restenosis seems to be equivalent for all these strategies with a restenosis rate of about 30% while after balloon angioplasty of diffuse (> 10 mm) stent restenosis restenosis rates range between 35% and 85%. From a pathophysiological point of view it seems conclusive that balloon angioplasty can only achieve a limited lumen by plastic deformation of the obstructive neointimal tissue, which is responsible for stent restenosis. In this situation techniques, which ablate the neointimal tissue, can create a more adequate lumen without extensive vessel trauma supported by lower restenosis rates between 25% and 56% compared to balloon angioplasty alone. Prospective randomized trial are needed in the future to support a superiority of ablative techniques over conventional balloon angioplasty for the treatment of stent restenosis.

Impact of routine angiographic follow-up after angioplasty

BACKGROUND

There is an ongoing controversy as to whether repeat coronary angiography should be routinely performed after successful percutaneous transluminal coronary angioplasty (PTCA).

METHODS

We examined the 10-year outcome in 400 patients who had or had not undergone an angiographic control 6 months after successful PTCA and a subsequent event-free 6-month period. Our comparison was based on data gathered by questionnaire and telephone interview in 315 patients with (group A) and 85 patients without (group B) a routine 6-month angiographic control. Multivariate analysis (Cox model) was performed to identify predictors of adverse events.

RESULTS

During the 10-year follow-up period, 22 (7%) of the 315 patients in group A died, compared with 16 (19%) patients in group B (P= .003). In groups A and B, respectively, acute myocardial infarction occurred in 28 (9%) and 10 (12%) patients (not significant [NS]); coronary artery bypass grafting (CABG) was performed in 42 (13%) and 14 (16%) patients (NS); repeat PTCA was performed in 89 (28%) and 11 (13%) patients (P= .012); and serious adverse events (death, myocardial infarction, CABG) occurred in 76 (24%) and 32 (38%) patients (P= .02). Absence of a 6-month angiographic follow-up was identified as an independent predictor of death associated with a 2.7 times higher mortality rate during the 10-year follow-up period. Previous myocardial infarction increased the risk of death 2.5 times. Any increase of residual diameter stenosis by 10% was combined with a 1.4 times higher mortality rate. The chance of bypass surgery was higher in patients with multivessel disease (2.9 times), in patients with unstable angina (2.1 times), and in case of an increase of residual diameter stenosis by 10% (1.3 times). No predictor for the risk of myocardial infarction was found. Angiographic follow-up increased the likelihood of PTCA 2.5 times.

CONCLUSIONS

A routinely performed angiographic control 6 months after successful PTCA is associated with a significantly higher rate of repeat PTCA but, most important, is correlated with a significantly lower mortality rate during the 10-year follow-up period.