Three dimensional fusion of electromechanical mapping and magnetic resonance imaging for real-time navigation of intramyocardial cell injections in a porcine model of chronic myocardial infarction

For cardiac regenerative therapy intramyocardial catheter guided cell transplantations are targeted to the infarct border zone (IBZ) i.e. the closest region of viable myocardium in the vicinity of the infarct area. For optimal therapeutic effect this area should be accurately identified. However late gadolinium enhanced magnetic resonance imaging (LGE-MRI) is the gold standard technique to determine the infarct size and location, electromechanical mapping (EMM) is used to guide percutaneous intramyocardial injections to the IBZ. Since EMM has a low spatial resolution, we aim to develop a practical and accurate technique to fuse EMM with LGE-MRI to guide intramyocardial injections. LGE-MRI and EMM were obtained in 17 pigs with chronic myocardial infarction created by balloon occlusion of LCX and LAD coronary arteries. LGE-MRI and EMM datasets were registered using our in-house developed 3D CartBox image registration software toolbox to assess: (1) the feasibility of the 3D CartBox toolbox, (2) the EMM values measured in the areas with a distinct infarct transmurality (IT), and (3) the highest sensitivity and specificity of the EMM to assess IT and define the IBZ. Registration of LGE-MRI and EMM resulted in a mean error of 3.01 ± 1.94 mm between the LGE-MRI mesh and EMM points. The highest sensitivity and specificity were found for UV <9.4 mV and bipolar voltage <1.2 mV to respectively identify IT of ≥5 and ≥97.5 %. The 3D CartBox image registration toolbox enables registration of EMM data on pre-acquired MRI during the EMM guided procedure and allows physicians to easily guide injections to the most optimal injection location for cardiac regenerative therapy and harness the full therapeutic effect of the therapy.

Assessment of left ventricular volumes, ejection fraction and mass

Aim: We compared and delineated possible differences of model-based analysis of ECGgated SPECT using 99mTc-sestamibi (Tc- SPECT) with ECG-gated 18F-fluorodeoxyglucose- PET (FDG-PET) for determination of enddiastolic (EDV) and end-systolic (ESV) cardiac volumes, left ventricular ejection fraction (LVEF), and myocardial mass (LVMM). Patients, methods: 24 patients (21 men; age: 54 ± 12years) with coronary artery disease underwent Tc-SPECT and FDG-PET imaging for evaluation of myocardial perfusion and viability. By using model-based analysis EDV, ESV, LVEF and LVMM were calculated from short axis images of both Tc-SPECT and FDGPET. Results: Left ventricular volumes by Tc- SPECT and FDG-PET were 176 ± 60 ml and 181 ± 59 ml for EDV, and 97 ± 44 ml and 103 ± 45 ml for ESV respectively, LVEF was 47 ± 8% by Tc-SPECT and 45 ± 9% by FDG-PET. The LVMM was 214 ± 40 g (Tc-SPECT) and 202 ± 43 g (FDG-PET) (all p = NS, paired t-test). A significant correlation was observed between Tc-SPECT and FDG-PET imaging for calculation of EDV (r = 0.93), ESV (r = 0.93), LVEF (r = 0.83) and LVMM (r = 0.72). Conclusion: ECG-gated Tc-SPECT and FDG-PET using two tracers with different characteristics (perfusion versus metabolism) showed close agreement concerning measurements of left ventricular volumes, contractile function and myocardial mass by using a model-based analysis.

Tracking the migration of cardially delivered therapeutic stem cells in vivo: state of the art

Cell-based therapy is a promising, novel therapeutic strategy for cardiovascular disease. The rapid transition of this approach from the benchside to clinical trials has left a gap in the understanding of the mechanisms of cell therapy. Monitoring of cell homing and the fate of cardially delivered stem cells is fundamental for clarification of the myocardial regenerative process. Noninvasive imaging techniques allow an in vivo evaluation of the survival, migration and differentiation of implanted stem cells over time, and by this means, can help to answer unresolved questions. The most promising in vivo tracking methods involve the direct, nonspecific labeling of cells including MRI, radionuclide imaging and the use of reporter-gene imaging. This review summarizes the most important results of animal and human studies in which the fate and biodistribution of cardially delivered stem cells are assessed through different in vivo tracking methods.

First in–human randomized comparison of an anodized niobium stent versus a standard stainless steel stent

OBJECTIVES

The purpose of this study was to test the hypothesis that a niobium stent might lower the restenosis rate in de novo coronary lesions as compared to a bare metal stent.

BACKGROUND

Recent data have suggested that inflammatory and allergic reactions to certain compounds in metal stents may play a role in the onset of restenosis. Thus, niobium as an inert material might be beneficial in lowering the rate of restenosis.

METHODS

In this single blind, two-center prospective trial patients were randomized into two groups; the first group (n=32) received a niobium stent (VELA STF), the second group (n=33) a bare metal stent (Antares STF). Clinical follow-up was performed at 1 and 6 months, angiographic and intravascular ultrasound analyses were performed at the 6-month follow-up.

RESULTS

All stents were successfully deployed. There was one stent thrombosis in each group. There were no significant differences concerning minimal lumen diameter, percent stenosis, and late lumen loss as assessed by intravascular ultrasound (IVUS) at the 6- month follow-up. At 30 days and at 6 months, there were no differences observed between the two groups regarding the rate of major cardiac adverse events. Immediately after stent implantation minimal lumen diameter was significantly larger (p=0.01) and residual percent stenosis significantly lower (p=0.01) in the niobium stent group.

CONCLUSION

The use of a niobium stent showed comparable results with other non-drug-eluting stents; however the inert qualities of this first generation niobium stent did not translate into a mid- or long-term benefit.

Endovascular brachytherapy for prophylaxis against restenosis after long-segment femoropopliteal placement of stents: initial results

PURPOSE

To evaluate the feasibility, safety, and effectiveness of endovascular brachytherapy for the prevention of restenosis after long-segment femoropopliteal percutaneous transluminal angioplasty (PTA) and stent implantation.

MATERIALS AND METHODS

Thirty-three patients (23 men, 10 women; mean age, 66 years) with femoropopliteal lesions (mean treated length, 17 cm; range, 4-30 cm) underwent PTA and stent implantation followed by brachytherapy with a centering catheter. A dose of 14 Gy was delivered to the adventitia by using an iridium 192 source. Long-term pharmacotherapy with acetylsalicylic acid was combined with clopidogrel for 1 month. Follow-up examinations included measurement of the ankle-brachial index, color-coded duplex ultrasonography, and angiography.

RESULTS

The overall 6-month recurrence rate was 30% (10 of 33 arteries). Seven patients developed sudden late thrombotic occlusion of the segment with the stent 3.5-6 months after stent implantation. Considering the overall results after successful local thrombolysis in six of these seven patients, only four (12%) of 33 arteries with a stent had in-stent restenosis caused by neointimal hyperplasia.

CONCLUSION

The study results are promising concerning the possibility of reducing in-stent restenosis by means of brachytherapy after long-segment femoropopliteal placement of stents. The high incidence of late thrombotic occlusion requires optimization of the antithrombotic regimen.

Online myocardial viability assessment in the catheterization laboratory via NOGA electroanatomic mapping: Quantitative comparison with thallium-201 uptake

BACKGROUND

The aim of this prospective study was to investigate the concordance between quantitative resting (201)Tl uptake as an established myocardial viability index and the electrical activity of the heart, determined by NOGA nonfluoroscopic electroanatomic mapping.

METHODS AND RESULTS

The myocardial resting and late resting thallium uptakes of 384 myocardial segments from 32 patients (27 males aged 65+/-8 years) with previous myocardial infarction and chronic stable angina were compared with unipolar voltage potentials and local shortening of the left ventricle as assessed by electroanatomic mapping. The quantitative thallium uptake data were analyzed by polar map analysis by division into 12 comparable myocardial segments, as represented in electroanatomic mapping images. Unipolar voltage potentials exhibited a significant logarithmic correlation with both resting and late resting thallium uptake (attenuation corrected: r=0.660 and r=0.744; non-attenuation corrected: r=0.623 and r=0.721). Receiver operator characteristic analyses revealed unipolar voltage cutoff points of 12.0 mV (predictive accuracy 0.853, P< 0.001; sensitivity/specificity 81%) for normal myocardium and 6.4 mV (predictive accuracy 0.901, P< 0.001; sensitivity/specificity 82%) for nonviable myocardium assessed by attenuation-corrected (201)Tl late resting images and of 12.7 mV (predictive accuracy 0.822, P<0.001; sensitivity/specificity 75%) and 6.5 mV (predictive accuracy 0.808, P<0.001; sensitivity/specificity 73%) for non-attenuation-corrected late resting (201)Tl images.

CONCLUSIONS

These results indicate that the unipolar voltage potentials obtained by electroanatomic mapping correlate well with standard quantitative late resting (201)Tl imaging for the evaluation of myocardial viability; thus, NOGA endocardial mapping provides useful "online" data at the time of catheterization, especially when information from other methods for viability assessment is unavailable.

Adaptive remodeling of the infarct-related artery is associated with recurrent ischemic events after thrombolysis in acute myocardial infarction

BACKGROUND

Recurrent ischemic events occur during the hospital stay of 7-32% of patients after successful thrombolytic treatment of acute myocardial infarction (AMI).

OBJECTIVE

To define the association between postinfarction angina pectoris and the clinical, angiographic, and intravascular ultrasound (IVUS) parameters of the infarct-related artery for consecutive prospectively included patients.

METHODS

Clinical, qualitative, and quantitative angiographic and IVUS data for 64 patients (56 men, aged 53+/-12 years) with thrombolysis of AMI were analyzed. All patients underwent coronary angiography and pre-interventional IVUS measurement electively within 1 month of AMI or at the time of the occurrence of postinfarction angina pectoris. Classification as adaptive or constrictive remodeling was according to whether the cross-sectional area of a vessel was larger or smaller than that of the proximal or distal reference segment.

RESULTS

Nineteen of the 64 patients (29.7%) suffered from recurrence of ischemic events (group 1), whereas 45 patients (60.3%, group 2) remained free from symptoms. In univariate analyses, multivessel disease (42 versus 24%, P= 0.0236) and adaptive remodeling (63 versus 24%, P= 0.0032) were found to occur more commonly among patients in group 1. The patients in group 1 exhibited larger total vessel cross-sectional areas than did the patients in group 2 (17.5+/-4.2 versus 14.9+/-6.1 mm2, P = 0.0556). In multivariate regression analysis, adaptive remodeling proved to be a significant predictor (P = 0.0145) of the recurrence of ischemic events after thrombolysis of AMI.

CONCLUSIONS

Adaptive remodeling of the infarct-related artery is associated with early postinfarction angina pectoris after thrombolysis of AMI.

Pre-existing arterial remodeling is associated with in-hospital and late adverse cardiac events after coronary interventions in patients with stable angina pectoris

OBJECTIVES

The goal of this study was to investigate the association between the atherosclerotic arterial remodeling and the incidence of cardiac events after coronary interventions in patients with stable angina.

BACKGROUND

The local mode of de novo atherosclerotic remodeling is associated with plaque vulnerability and clinical symptoms. It may, therefore, reflect plaque morphology influencing the long-term outcome after coronary interventions.

METHODS

Quantitative angiography and intravascular ultrasound were obtained in 244 patients with stable angina before and after single-vessel revascularization. On the basis of the lesion and the reference segment vessel size, patients were categorized into three groups (adaptive [AR], constrictive [CR] and intermediate [IR] remodeling). The lesion was analyzed for lumen, total vessel and plaque areas. Clinical follow-up was obtained at a mean period of 7.7+/-3.7 months.

RESULTS

Patients with CR had a higher rate of in-hospital complications (10.9% vs. 2.9% and 2.7% in group CR vs. AR and IR, p = 0.035). In contrast, patients with AR had the highest rate of major adverse cardiac events (MACE) (44.3% vs. 25.5% in IR and 28.1% in CR, p = 0.024) with a predominance of revascularization at follow-up. Both target lesion restenosis (p = 0.036) and nontarget lesion de novo stenosis (p = 0.007) occurred more frequently in this group. Adaptive remodeling was a significant predictor of MACE in multivariate analysis.

CONCLUSIONS

Adaptive remodeling is associated with a higher rate of MACE, target lesion restenosis and nontarget de novo stenosis. This finding may be due to differential responses of the adaptively remodeled vessel to revascularization and a generally accelerated course of systemic atherosclerosis.

Longitudinal straightening effect of stents is an additional predictor for major adverse cardiac events. Austrian Wiktor Stent Study Group and European Paragon Stent Investigators

OBJECTIVES

The aim of this study was to perform an investigation of the effects of the longitudinal straightening of coronary arteries by stents and the possible association with major adverse cardiac events (MACE) (primary end point) and angiographic restenosis (secondary end point).

BACKGROUND

Stent deployment straightens a tortuous artery, and any consequent arterial longitudinal stretch may contribute to MACE and stent restenosis severity.

METHODS

Clinical, qualitative and quantitative angiographic data on 404 patients with single stent implantation were subjected to multivariate nominal logistic regression analysis for the prediction of MACE. The predictive accuracy, sensitivity and specificity values and cut-off points of the continuous variables were determined via receiver operating characteristics curves. The longitudinal straightening effect of stents was characterized through the changes in vessel angle (defined by the tangents to the proximal and distal parts of the stenoses/stents).

RESULTS

Follow-up angiography on 354 patients revealed 73 cases of stent restenosis (> or =50% diameter stenosis). Coronary bypass surgery was performed in 4 patients and repeated percutaneous transluminal coronary angioplasty in 56 patients; acute myocardial infarction (AMI) occurred in 2 patients, and 4 patients died during the follow-up. The overall incidence of MACE (death, AMI and revascularization) was 16.3% (66 patients). The best predictive accuracies and sensitivities/specificities of factors indicative of MACE were found for the minimal lumen diameter (MLD) at follow-up (predictive accuracy: 0.9305, sensitivity/specificity: 86.6%), the post-stent MLD (0.773, 77.2%), the percent diameter stenosis (%DS) at follow-up (0.9432, 87.1%), the prestent vessel angulation (0.6797, 68.2%) and the poststent changes in vessel angulation (0.6279, 62.2%). Multivariate nominal logistic regression analysis demonstrated that a poststent MLD < or =2.63 mm (p = 0.0017, odds ratio [OR] = 17.961, 95% confidence interval [CI] = 17.45-20.428), an MLD at follow-up < or =1.7 mm (p = 0.0059, OR = 11.880, 95% CI = 11.490-14.093), a %DS at follow-up > or =42.2% (p = 0.0000, OR = 49.553, 95% CI = 48.024-53.507), a prestent vessel angulation > or =33.5 degrees (p = 0.0477, OR = 5.404, 95% CI = 5.382-7.142) and poststent changes in vessel angulation > or =9.1 degrees (p = 0.0026, OR = 19.161, 95% CI = 18.562-21.750) were significant predictors for MACE. Multiple linear regression revealed that the poststent MLD (multivariate p = 0.0001), the MLD at follow-up (p = 0.0000), the prestent vessel angulation (p = 0.0431) and the changes in vessel angulation after stent implantation (p = 0.0316) were significant independent variables predicting angiographic stent restenosis severity.

CONCLUSIONS

The longitudinal straightening effect of coronary artery stents contributes significantly to the occurrence of MACE and angiographic restenosis, and this finding may have an impact on future stent design.

Arterial remodelling of native human coronary arteries in patients with unstable angina pectoris: a prospective intravascular ultrasound study

OBJECTIVE

To investigate the use of intravascular ultrasound (IVUS) in detecting the presence of arterial remodelling in patients with unstable angina.

DESIGN

Prospective case study.

PATIENTS

60 of 95 consecutively admitted patients with unstable angina (41 male, 19 female), mean (SD) age 61.2 (8.1) years.

INTERVENTIONS

Qualitative and quantitative coronary angiography and IVUS.

MAIN OUTCOME MEASURES

Adaptive or constrictive remodelling (AR, CR) was considered present when the cross sectional area of the external elastic membrane at the lesion site was larger than the proximal cross sectional area or smaller than the distal cross sectional area, respectively.

RESULTS

22 of the 60 patients (37%) showed AR and 14 (23%) showed CR. No remodelling was seen in 24 patients (group NR). The plaque contained more thrombus and plaque rupture in group AR than in groups CR and NR (thrombus: 91% v 50% and 67%, respectively, p = 0.023; rupture: 73% v 29% and 42%, p = 0.020). AR was associated with a larger plaque cross sectional area (12.6 (SD 4.6) mm2 v 10.8 (6.3) and 9.2 (3.7) mm2, p = 0.001) and larger external elastic membrane cross sectional area (16.5 (5.8) mm2 v 13.2 (5.2) and 14.4 (3.6) mm2, p = 0.01 in group AR v groups CR and NR, respectively), while the plaque burden was larger in groups AR (74.9 (9.1)%) and CR (72.4 (16.6)%) than in group NR (66.2 (18.1)%, p = 0.005).

CONCLUSIONS

IVUS is capable of detecting adaptive and constrictive remodelling of target lesions and its relation to plaque morphology in unstable angina.

[Cardiovascular complications of pancreatis diseases]

Under physiological conditions, the pancreas scarcely influences the function of the cardiovascular system, although the hormones produced in the healthy pancreas (insulin, glucagon and somatostatin) affect the myocardial contractility in pharmacological doses. Among the diseases of the pancreas, the pancreatic tumours (insulinoma, glucagonoma and vipoma), furthermore the acute and chronic pancreatitis involve cardiovascular complications, which influence the outcome of the disease. Although the clinical picture is dominated by the metabolic changes of the excessively produced hormones in pancreatic tumours, the cardiac and vascular effects of the hormones may be considerable. In acute necrotizing pancreatitis, enzymes released from the pancreas and inflammatory mediators transform acute necrotizing pancreatitis into "multiple organ disease"; one of the important forms of this disease is the cardiovascular shock syndrome. One of the best-known complications of chronic pancreatitis is the pancreoprive diabetes mellitus, and beside that other, nonspecific cardiac alterations (e.g. ECG-changes) may occur.

Acute myocardial infarction enhances the portal venous histamine level in dogs

OBJECTIVE AND DESIGN

The aim of our experiments was to determine the plasma histamine level in the portal venous (VP) blood during acute coronary occlusion and reperfusion.

SUBJECTS

27 adult mongrel dogs of either sex were randomized for three groups: sham-operated controls, occlusion group (group O) and reperfusion group (group R).

TREATMENT

The left circumflex coronary artery (LCx) was proximally occluded and the occlusion was maintained during 6 h (group O), or after a 60-min occlusion the LCx was reperfused (group R). The portal vein was cannulated to take blood samples for hormone measurements.

METHODS

The plasma histamine concentrations were measured with the radioenzymatic method.

RESULTS

The VP plasma histamine level was significantly increased 60 min after the LCx occlusion in groups O (99.9 +/- 40.2 vs. 252.9 +/- 100 pg/ml, mean +/- SD) and R (101.2 +/- 55.1 vs. 179.8 +/- 96 pg/ml), and remained high in group O (240.4 +/- 81 pg/ml), while 2 h after LCx reperfusion it had decreased to the basic level. There was no correlation between the hemodynamic parameters and the portal vein plasma histamine levels.

CONCLUSIONS

Histamine is released into the gastrointestinal tract during acute myocardial ischemia and reperfusion, but the release of the vasoactive drug has no effect on systemic hemodynamics.

Myocardial and gastrointestinal release of vasoactive intestinal peptide during experimental acute myocardial infarction

BACKGROUND

Vasoactive intestinal peptide (VIP) acts as a vasodilator on coronary and gastrointestinal arteries. During coronary occlusion, the locally released VIP may exert a protective effect on the heart, but it may aggravate the shock state through its vasodilatory effect in the gastrointestinal tract.

METHODS

After left thoracotomy, the left circumflex coronary artery (LCx) was prepared, and a pneumatic occluder was introduced around it. After 60 min of coronary occlusion, the LCx was reperfused in six dogs (reperfusion group), while in another six the occlusion was maintained for 6 h (occlusion group). Five dogs served as sham-operated controls. The plasma concentration of VIP was determined at baseline, after the 60 min occlusion and 10 min, 3 h and 6 h after reperfusion, or 3 h and 6 h after continuous occlusion in the coronary sinus and in the femoral and portal veins.

RESULTS

The plasma VIP concentrations in all three vessels were increased after 60 min of LCx occlusion. During the 6 h constant coronary occlusion, concentrations remained increased in both the coronary sinus and the portal vein, but not in the femoral vein. In the reperfusion group, 10 min after reperfusion, the plasma concentrations of VIP in all three vessels had decreased.

CONCLUSIONS

Coronary artery occlusion causes a long-term increase in plasma VIP concentrations that decreases after reperfusion, when measured in the portal vein and coronary sinus, but not in the femoral veins.

Noninvasive monitoring of hemodynamic changes in acute pancreatitis in rabbits

Hemodynamic parameters of experimental acute necrotizing pancreatitis (AP) were monitored by means of echocardiography in rabbits. Left ventricular (LV) systolic and diastolic parameters were determined before and 1, 3, 6, 12, 18, and 24 hr after injection of taurocholic acid in the pancreatic duct in AP animals. Temporary LV dilatation was observed 6 hr after the AP induction [LV end-diastolic (ED) diameter from 1.16 +/- 0.04 to 1.22 +/- 0.04 cm, P < 0.05, ED volume from 2.98 +/- 0.34 to 3.57 +/- 0.75 ml, P < 0.05] without decrease in systolic function. Cardiac output (CO) and stroke volume (StV) was increased in both groups 3 hr after the operation (from 0.53 +/- 0.15 to 0.71 +/- 0.06 L/min, P < 0.05 in AP), but in the AP animals it remained high. However, 24 hr after AP induction, both the CO and the StV were decreased significantly. The LV diastolic function was impaired 1 hr after AP induction, but had recovered after 12 hr. In conclusion, an early diastolic impairment followed by LV enlargement could be noninvasively observed in experimental AP in rabbits.

Elevated levels of plasma vasoactive intestinal peptide in human acute myocardial infarction

The plasma levels of vasoactive intestinal peptide in peripheral vein were measured in human acute myocardial infarction. The plasma vasoactive intestinal peptide level was increased within 1 h after the onset of the symptoms of acute myocardial infarction (Group 1, n = 9), compared with normal values (6.3 +/- 0.7 vs. 2.8 +/- 0.9 pg/ml, P < 0.05). Two or more hours after the onset of acute myocardial infarction there was no subsequent increase in peripheral plasma vasoactive intestinal peptide levels (n = 26). Ten days after the onset of acute myocardial infarction, the elevated plasma vasoactive intestinal peptide levels in Group 1 had normalized (3.5 +/- 0.5 pg/ml).

Cardiac manifestations in primary Sjögren's syndrome

OBJECTIVE

To determine cardiac manifestations in primary Sjögren's syndrome (SS).

METHODS

Echocardiographic examination was undertaken in 64 patients (62 women, two men) with primary SS (54 definite (DSS) and 10 probable (PSS)) who had systemic symptoms. Twenty one healthy women volunteers of similar age acted as controls.

RESULTS

Acute exudative pericarditis occurred in only one patient. An echogenic pericardium was demonstrated in 21 patients (19 DSS, two PSS) (33%) who had a previous symptom free pericarditis, but in none of the controls. Pulmonary pressure was significantly greater in the patients than in the controls (31 (SD 8) mm Hg compared with 24 (7) mm Hg), but there was no significant difference between the DSS and PSS groups. Left ventricular (LV) systolic function was similar in patients and controls. Twenty two patients (20 DSS, two PSS) and one control subject were excluded from LV diastolic function evaluation because of conditions likely to influence the parameters. Of the remaining 42 patients with SS (34 DSS, eight PSS), 21 (17 DSS, four PSS) had impaired diastolic function, confirmed by several diastolic parameters. LV diastolic dysfunction and echogenic pericardium occurred independently of each other, and there was no correlation between the occurrence of these silent cardiac abnormalities and the clinical and laboratory findings.

CONCLUSIONS

Obvious cardiac involvement is rare in primary SS, but clinically silent manifestations (symptom free pericarditis and LV diastolic dysfunction) are common. The clinical and prognostic significance of these changes cannot yet be defined.

[15-year echocardiographic follow-up of acromegalic patients]

An echocardiographic follow-up of 25 patients (pts) was performed, after the first examinations in 1978-1979. 15 pts have died in the last 15 years (Group 1), while 10 still living (Group 2). In Group 1 either the impaired global left ventricular at the time of the first echocardiography predicted a high mortality i.e. there were only two pts with normal echocardiographic findings. The other 6 acromegalic pts with a "normal heart" have survived. The left ventricular hypertrophy of pts in Group 2 was observed to increase during the 15-year follow-up, because of the development of systemic hypertension. In conclusion, the echocardiographic findings are of a good predictive value in estimations of the survival rate in acromegalic pts.

Coronary artery stenosis and occlusion: value of 99Tcm-MIBI SPECT

The aim of this study was to evaluate and validate a new quantification method for 99Tcm-sestamibi single photon emission computed tomographic (SPECT) myocardial imaging based on a four-slice analysis method and to check the functional results of percutaneous transluminal coronary angioplasty (PTCA). Using the calculated pathological area of the scintigram as an index for myocardial ischaemia, the overall sensitivity was 81-90% and the overall specificity was 74-98%. Analysis of variance of the repeated measurements revealed good reproducibility (coefficient of variation 8.4%). A significant correlation was found between the size of the exercise-induced perfusion defects and the degree of coronary stenosis. The comparison of radionuclide ventriculography and the perfusion image in 27 patients revealed a good correlation between the resting global ejection fraction and myocardial perfusion, but there was no correlation during exercise, indicating a dissociation between myocardial perfusion and function during exercise conditions in patients with coronary artery disease (CAD). Patients with total coronary occlusions showed more resting defects than patients with partial stenoses. Both groups benefit from PTCA or re-opening of chronic coronary occlusion, respectively. Exercise-induced myocardial ischaemia significantly decreased, and in 36% of the patients with previous myocardial infarction a significant reduction of the size of the resting perfusion defects occurred. In conclusion, our quantification method is suitable for the accurate non-invasive diagnosis of CAD, and for the follow-up of the invasive treatment of coronary artery stenoses and occlusions.

[Improvement in myocardial function and perfusion after recanalizing a chronic coronary artery occlusion]

The purpose of the study was to evaluate the improvement of the left ventricular ejection fraction and myocardial perfusion after recanalization of chronic coronary artery occlusions. The patients were investigated by rest and exercise radionuclide ventriculography (25/31) and rest and exercise myocardial scintigraphy (22/31). The examinations were performed 3 +/- 1 days before and within 7 days and 4 months after recanalization. Exercise-induced chest pain was present in 77% (24/31) of the patients before, in 10% (3/31) after recanalization and in 23% (7/31) during follow-up. Six of the 7 patients with exercise-induced chest pain after 4 months developed restenosis in the former reopened coronary artery. The results of the exercise-ECG present that 71% (22/31) of the patients had ST-segment-depression before, 19% (6/31) after catheter-intervention and 26% (8/31) during follow-up. Six of the 8 patients with exercise-induced ST-depression after 4 months had a restenosis in the former reopened coronary artery. Reopening resulted in an increase of global rest ejection fraction (EF) from 51 +/- 11% to 54 +/- 13% (p < 0.05) and sectorial EF from 56 +/- 17% to 61 +/- 21% (p < 0.01) after recanalization. After 4 months patients with excellent angiographic results still had an increased global and sectorial EF at rest (global: 54 +/- 9%, sectorial: 59 +/- 17%; n.s.). Patients with restenosis (note: no reocclusion) developed a decrease of global and sectorial rest EF (global: 49 +/- 14%, sectorial: 57 +/- 19%; n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

[Myocardial function before and after reopening of chronic coronary occlusion]

To assess the myocardial function before and after reopening of chronic coronary artery occlusions, 20 patients were investigated at rest and during exercise with ECG and equilibrium radionuclide ventriculography. The recanalisation of the chronically occluded vessel was carried out by means of Rotacs-catheter in 17 patients, of a guide wire enforced by recanalisation-catheter in 2 patients and of a thin guide wire alone in 1 patient, always followed by conventional balloon angioplasty. After successful PTCA the average coronary artery stenosis diameter decreased from 100% to 34 +/- 6%. Angina pectoris and/or dyspnea observed during exercise were improved in 83% of the patients. The radionuclide global left ventricular ejection fraction at rest increased from 55 +/- 9% to 59 +/- 10% (p < 0.05), and during exercise from 52 +/- 12% to 61 +/- 12% (p < 0.05). The improvement in global ejection fraction at rest was more pronounced in 5 patients, who suffered from angina pectoris at rest before PTCA (from 56 +/- 4% to 65 +/- 9%, p < 0.05). It is concluded that reopening of chronically occluded coronary arteries in properly selected patients leads to a significant improvement of the global left ventricular function at rest and during exercise.

[Prevention of postsurgical thromboembolism with small doses of heparin]

The study includes 390 patients of different age, operated for various conditions during the last quarter of 1975, and systematically treated post operatively with heparin (the cases in which heparin was contraindicated were not included). None of the patients developed signs of thromboembolism after the operation. The drawbacks of the method are virtually inexistent as compared to the gravity of postoperative thrombolic complications. A further study included 1708 operated patients of whom 223 (13.0%) received the heparin treatment and 1485 (87.0%) did not. There was no thrombolic-embolic complication in the former lot and 12 cases (0.8%) in the latter. Three of 15 patients (20%) in whom the postoperative heparin treatment was interrupted immediately or very soon, developed thromboembolism. The method is efficient provided it is applied after the operation up to complete mobilization of the patient. The method is readily applicable, there is no risk and haemostasis is insured.