Diagnostic and prognostic contribution of DPD scintigraphy in transthyretin V30M cardiac amyloidosis

BACKGROUND

Early diagnosis and prognostic stratification of cardiac transthyretin amyloidosis are crucial. Although 99mTc 3,3-diphosphono-1,2-propanedicarboxylic acid (DPD) scintigraphy is the preferred method for the non-invasive diagnosis, its accuracy appears to be limited in transthyretin amyloidosis protein (ATTR) V30M mutation. Furthermore, its prognostic value in this mutation is unknown. This study investigated the diagnostic value of DPD scintigraphy to detect ATTR cardiomyopathy in V30M mutation and explored its prognostic value regarding mortality.

METHODS

A total of 288 ATTR V30M mutation carriers (median age: 46 years; 49% males) without myocardial thickening (defined as septal thickness ≥13mm) attributable to other causes and who underwent DPD scintigraphy were enrolled. ATTR cardiomyopathy was defined by septal thickness ≥13mm and at least one of the criteria: late heart-to-mediastinum (H/M) 123I-metaiodobenzylguanidine (MIBG) uptake ratio <1.60; electrical heart disease or biopsy-documented amyloidosis.

RESULTS

ATTR cardiomyopathy was identified in 41 (14.2%) patients and cardiac DPD uptake in 34 (11.8%). During a mean follow-up of 33.6 ± 1.2 months, 16 patients died (5.6%). Mortality was 14 times higher in patients with ATTR cardiomyopathy, 13 times higher in those with DPD uptake and 10 times higher in those with late H/M MIBG <1.60. The combined assessment of septal thickness and cardiac DPD uptake improved risk stratification: patients without septal thickening and without DPD retention had an excellent prognosis while those who presented either or both of them had a significantly worse prognosis, with 5-year mortality rates ranging from 39.9 to 53.3%.

CONCLUSIONS

DPD scintigraphy is useful for prognostic stratification of ATTR V30M mutation carriers. Patients without septal thickening and no DPD uptake present the best prognosis compared to those with any signs of cardiac involvement.

A Case of Success: Complete Response to Radium-223 in Metastatic Castration-Resistant Prostate Cancer

Radium-223 dichloride (Ra223) is the first targeted alpha agent approved for treating metastatic castration-resistant prostate cancer (mCRPC) with bone-exclusive disease. A benefit in overall survival and time to the first symptomatic skeletal-related event was shown in the Alpharadin in Symptomatic Prostate Cancer Patients (ALSYMPCA) trial. However, this trial did not describe a bone scan response to Ra223, and there is no universal consensus about how it should be monitored. Furthermore, a scintigraphy flare phenomenon may lead to false-positive tracer uptake in responsive cases, thereby misleading the interpretation of imaging results.  We present the case of a 67-year-old male with mCRPC and exclusive bone disease treated with Ra223. The bone scintigraphy after the end of the treatment showed an apparent aggravation of the lesions, corresponding to a flare phenomenon, with an almost complete resolution after three months. The patient maintained a scintigraphic response for seven months.

Diagnostic and prognostic contribution of 99mTc-DPD scintigraphy in transthyretin V30M cardiac amyloidosis

Background

Early diagnosis and prognostic stratification of hereditary transthyretin amyloidosis (ATTR) are crucial. Previous findings suggested that 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scintigraphy presents suboptimal accuracy to detect ATTR cardiomyopathy caused by V30M mutation, particularly in patients with onset of symptoms under 50 years of age. Furthermore, its prognostic value has never been evaluated in ATTR caused by this mutation.

Purpose

To assess the diagnostic value of DPD scintigraphy to detect cardiomyopathy in a large cohort of patients with ATTR-V30M mutation and to explore its prognostic value regarding mortality.

Methods

Of the 305 ATTR-V30M mutation carriers followed prospectively and who underwent DPD scintigraphy, 288 individuals [median age 46 (39–56); 49% male] without myocardial thickening attributable to other causes were enrolled in the study. Amyloid cardiomyopathy was defined by septal thickness ≥13mm not attributable to other causes plus at least one of the following criteria: (1) late heart-to-mediastinum (H/M) 123I-metaiodobenzylguanidine (MIBG) ratio &lt;1.60; (2) electrical heart disease (arrhythmia or cardiac conduction defect); or (3) amyloid infiltration documented in biopsy.

Results

Amyloid cardiomyopathy was identified in 41 (14.2%) patients and 44 (15.3%) individuals presented abnormal cardiac DPD uptake. Individuals with cardiac DPD retention had 27-fold higher likelihood of having amyloid cardiomyopathy (OR: 27.4; 95% CI 11.6–65.0; P&lt;0.001). However, DPD scintigraphy presented suboptimal accuracy to detect ATTR cardiomyopathy (89.9%) with limitations in sensitivity (56.1%), specificity (95.6%), positive predictive value (67.7%) and negative predictive value (92.9%).

During a mean follow-up 33.6±1.2 months, 16 patients died (5.6%). Mortality was 14 times higher in patients with amyloid cardiomyopathy (HR: 14.1; 95% CI 4.9–40.7; P&lt;0.001), 13 times higher in those with abnormal cardiac DPD uptake (HR: 12.59; 95% CI % 4.56–34.72; P&lt;0.001) and 10 times higher in those with H/M MIBG ratio &lt;1.60 (HR: 10.40; 95% CI 2.95–36.69; P&lt;0.001). The prognostic value of ventricular thickness and cardiac DPD uptake was additive: patients without septal thickening and no cardiac DPD retention had excellent prognosis (5-year mortality of 0.75%), while those with septal thickening and/or abnormal DPD retention presented 5-year mortality rates ranging from 39.9 to 53.3%.

Conclusions

DPD scintigraphy is valuable in the evaluation of ATTR-V30M mutation carriers, particularly for prognostic stratification purposes, identifying patients at higher risk of death.

Funding Acknowledgement

Type of funding sources: None.

Impact of COVID-19 Pandemic on Cardiovascular Testing in Asia

Background

The coronavirus disease-2019 (COVID-19) pandemic significantly affected management of cardiovascular disease around the world. The effect of the pandemic on volume of cardiovascular diagnostic procedures is not known.

Objectives

This study sought to evaluate the effects of the early phase of the COVID-19 pandemic on cardiovascular diagnostic procedures and safety practices in Asia.

Methods

The International Atomic Energy Agency conducted a worldwide survey to assess changes in cardiovascular procedure volume and safety practices caused by COVID-19. Testing volumes were reported for March 2020 and April 2020 and were compared to those from March 2019. Data from 180 centers across 33 Asian countries were grouped into 4 subregions for comparison.

Results

Procedure volumes decreased by 47% from March 2019 to March 2020, showing recovery from March 2020 to April 2020 in Eastern Asia, particularly in China. The majority of centers cancelled outpatient activities and increased time per study. Practice changes included implementing physical distancing and restricting visitors. Although COVID testing was not commonly performed, it was conducted in one-third of facilities in Eastern Asia. The most severe reductions in procedure volumes were observed in lower-income countries, where volumes decreased 81% from March 2019 to April 2020.

Conclusions

The COVID-19 pandemic in Asia caused significant reductions in cardiovascular diagnostic procedures, particularly in low-income countries. Further studies on effects of COVID-19 on cardiovascular outcomes and changes in care delivery are warranted.

The sensitivity of DPD scintigraphy to detect transthyretin cardiac amyloidosis in V30M mutation depends on the phenotypic expression of the disease

Background: There is a growing need for a non-invasive test to detect cardiac involvement in patients with transthyretin-related hereditary amyloidosis (ATTR) caused by V30M mutation. ^99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scintigraphy is a promising method, but its accuracy in this particular mutation remains unknown.Methods: A cohort of 179 patients: 92 with early-onset disease (EoD, symptoms <50-years-old), 33 with late-onset disease (LoD) and 54 asymptomatic carriers were prospectively evaluated and underwent DPD scintigraphy, which was compared with the results of echocardiogram, ambulatory blood pressure monitoring, 24 h-Holter, myocardial ¹²³I-metaiodobenzylguanidine imaging and NT-proBNP.Results: Amyloid cardiomyopathy, defined as septal thickness ≥13 mm, was present in 32 patients (17.9%) and was more frequent in those with LoD (OR: 3.68, p = .003). Cardiac DPD uptake was present in 22 individuals (12.3%) and correlated with parameters indicative of cardiac amyloidosis. DPD imaging was strongly influenced by the age of disease onset: among patients with myocardial thickening, cardiac DPD retention was present in 11/15 (73.3%) with LoD, in contrast to only 4/17 (26.7%) with EoD (p = .005). Two patients with myocardial thickening and normal DPD scintigraphy underwent endomyocardial biopsy that confirmed ATTR amyloidosis.Conclusion: DPD scintigraphy presents suboptimal sensitivity to detect cardiac involvement in ATTRV30M, particularly in symptomatic patients with EoD.

Technetium-99m Labelling of the IOR CEA 1 Monoclonal Antibody: Evaluation of Different Methods

Aim: The aim of this study was to investigate the in vivo and in vitro properties of 99mTc labelled monoclonal antibody, IOR CEA 1 when radio-labelled by different methods. Methods: To achieve that purpose IOR CEA was directly radiolabeled via 2-mercaptoethanol (2-Me) and stannous ion (SnCI2) reduction and indirectly via the 2-iminothiolane (2-lm) conjugation. The resulting 99mTc-MoAbs were analysed for number of free sulfhydryl groups, chemical and radiochemical purity (checked by HPLC and SDS PAGE), immunoreactivity and biological distribution in mice. Results: Experimental results indicated a similar radiochemical purity and immunoreactivity for direct labelling methods and a decrease of both for 2-lm method. 2-Me antibody reduction led to a high antibody fragmentation as indicated by non-denaturing SDS PAGE analysis. Nevertheless SnCI2 and 2-lm labels revealed lower in vivo stability. Conclusion: 99mTc-(2-Me) IOR CEA presented favorable in vitro and in vivo properties. Therefore this label was compared to 99mTc-monoclonal antibody BW 431/26. Similar characteristics were found. Clinical studies also revealed identical biodistribution profile.

Reduced myocardial 123-iodine metaiodobenzylguanidine uptake: a prognostic marker in familial amyloid polyneuropathy

BACKGROUND

Transthyretin familial amyloid polyneuropathy is a hereditary form of amyloidosis characterized by sensorimotor and autonomic neuropathy, cardiac conduction defects, and infiltrative cardiomyopathy. Previous studies have suggested that myocardial sympathetic denervation assessed by 123-iodine metaiodobenzylguanidine (MIBG) imaging occurs early in disease progression. However, its prognostic significance was never evaluated. We aimed to study the long-term prognostic value of myocardial sympathetic denervation detected by MIBG imaging in transthyretin familial amyloid polyneuropathy.

METHODS AND RESULTS

A total of 143 individuals with V30M transthyretin mutation underwent Holter, ambulatory blood pressure monitoring, echocardiography, and MIBG imaging. Time to all-cause death was compared with late heart-to-mediastinum MIBG uptake ratio (H/M; either in relation to the estimated lower limit of normal [1.60] or as a continuous variable) using Cox proportional hazards regression. Multivariable analyses were performed to test the prognostic accuracy of clinical, neurological, and cardiovascular parameters. During a median follow-up of 5.5 years, 32 (22%) patients died. Five-year mortality rate was 42% for late H/M <1.60 and 7% for late H/M ≥1.60 (hazard ratio, 7.19; P<0.001). Late H/M was identified as an independent prognostic predictor. Fifty-three patients were submitted to liver transplantation. In comparison with neurophysiological score-matched controls, transplanted patients had lower long-term mortality (hazard ratio, 0.32; P=0.012). Patients with late H/M<1.60 were at higher risk of unfavorable outcome but seemed to have benefited from liver transplantation.

CONCLUSIONS

Cardiac sympathetic denervation as assessed by MIBG imaging is a useful prognostic marker in transthyretin familial amyloid polyneuropathy.

Distrofia simpática reflexa

Reflex Sympathetic Dystrophy is rare in pediatrics. It is a complex regional pain syndrome, of unknown etiology, usually post-traumatic, characterized by dysfunctions of the musculoskeletal, vascular and skin systems: severe persistent pain of a limb, sensory and vascular alterations, associated disability and psychosocial dysfunction. The diagnosis is based in high clinical suspection. In children and adolescents there are aspects that are different from the adult ones. Excessive tests may result in worsening of the clinical symptoms. Bone scintigraphy can help. Pain treatment is difficult, not specific. Physical therapies and relaxation technics give some relief. Depression must be treated. This syndrome includes fibromyalgia and complex regional pain syndrome type I. We present a clinical report of an adolescent girl, referred for pain, cold temperature, pallor and functional disability of an inferior limb, all signals disclosed by a minor trauma. She had been diagnosed depression the year before. The bone scintigraphy was a decisive test. The treatment with gabapentin, C vitamin, physiotherapy and pshycotherapy has been effective.

[Reflex sympathetic dystrophy]

Reflex Sympathetic Dystrophy is rare in pediatrics. It is a complex regional pain syndrome, of unknown etiology, usually post-traumatic, characterized by dysfunctions of the musculoskeletal, vascular and skin systems: severe persistent pain of a limb, sensory and vascular alterations, associated disability and psychosocial dysfunction. The diagnosis is based in high clinical suspection. In children and adolescents there are aspects that are different from the adult ones. Excessive tests may result in worsening of the clinical symptoms. Bone scintigraphy can help. Pain treatment is difficult, not specific. Physical therapies and relaxation technics give some relief. Depression must be treated. This syndrome includes fibromyalgia and complex regional pain syndrome type I. We present a clinical report of an adolescent girl, referred for pain, cold temperature, pallor and functional disability of an inferior limb, all signals disclosed by a minor trauma. She had been diagnosed depression the year before. The bone scintigraphy was a decisive test. The treatment with gabapentin, C vitamin, physiotherapy and pshycotherapy has been effective.

Análise custo-efectividade do samário-153-EDTMP versus terapêutica convencional da dor em doentes com metástases ósseas múltiplas dolorosas em Portugal

Prostate cancer is a significant cause of morbidity and mortality. In Portugal alone, according to a study published in 2003, the rate of new prostate cancer cases were 53 per 100,000 men (in 2000), with an age-standardized mortality rate of about 28 per 100,000 (in 1995). Multiple bone metastases are one of the major complications of advanced prostate cancer. Samarium-EDTMP showed to be a safe and effective alternative for palliative treatment of bone metastases. The goal of this economic study is to assess the cost-effectiveness of Samarium-153-EDTMP for the treatment of pain due to multiple bone metastases in hormone-refractory prostate cancer versus conventional pain therapy, in Portugal.Cost-effectiveness study that compares the expected direct costs to the National Health System of managing patients with painful multiple bone metastases with Samarium-153-EDTMP versus conventional pain therapy, in Portugal, in a 4-moths period.The total direct 4 months cost was 2,311.91 euro for a patient treated with Samarium-153-EDTMP versus 2,450.74 euro for a patient under standard treatment. According to the model a patient treated with Samarium-153-EDTMP represents a 138.83 euros saving.Samarium-153-EDTMP was not only a very effective therapeutic option but also an option with less cost than the conventional pain therapy, in patients with pain due to multiple bone metastases, in Portugal.

[Cost-effectiveness of samarium-153-EDTMP for the treatment of pain due to multiple bone metastases in hormone-refractory prostate cancer versus conventional pain therapy, in Portugal]

INTRODUCTION

Prostate cancer is a significant cause of morbidity and mortality. In Portugal alone, according to a study published in 2003, the rate of new prostate cancer cases were 53 per 100,000 men (in 2000), with an age-standardized mortality rate of about 28 per 100,000 (in 1995). Multiple bone metastases are one of the major complications of advanced prostate cancer. Samarium-EDTMP showed to be a safe and effective alternative for palliative treatment of bone metastases. The goal of this economic study is to assess the cost-effectiveness of Samarium-153-EDTMP for the treatment of pain due to multiple bone metastases in hormone-refractory prostate cancer versus conventional pain therapy, in Portugal.

METHODOLOGY

Cost-effectiveness study that compares the expected direct costs to the National Health System of managing patients with painful multiple bone metastases with Samarium-153-EDTMP versus conventional pain therapy, in Portugal, in a 4-moths period.

RESULTS

The total direct 4 months cost was 2,311.91 euro for a patient treated with Samarium-153-EDTMP versus 2,450.74 euro for a patient under standard treatment. According to the model a patient treated with Samarium-153-EDTMP represents a 138.83 euros saving.

CONCLUSION

Samarium-153-EDTMP was not only a very effective therapeutic option but also an option with less cost than the conventional pain therapy, in patients with pain due to multiple bone metastases, in Portugal.

Early detection of sympathetic myocardial denervation in patients with familial amyloid polyneuropathy type I

INTRODUCTION

Type I familial amyloid polyneuropathy (FAP I) is an autosomal dominant inherited disorder due to a genetic defect in transthyretin and is characterized by deposition of amyloid in various organs and tissues. The principal manifestations are related to polyneuropathy and dysautonomia. The aim of this study was to assess cardiac involvement and to correlate the findings with neurological status.

METHODS

34 patients with FAP (15 male and 19 female; mean age 43 +/- 15 years) underwent I123-labeled metaiodobenzylguanidine (MIBG) myocardial scintigraphy in order to evaluate cardiac sympathetic innervation. In addition they underwent ambulatory blood pressure monitoring (ABPM) and two-dimensional and Doppler echocardiography. Neurological involvement was quantified according to a neurophysiologic score (EMG; 0 = no abnormality and 100% = maximal disability).

RESULTS

The mean value of cardiac MIBG uptake was 1.75 +/- 0.5 (normal = 2.6 +/- 0.3) and correlated inversely with the EMG score (r = -0.67; p = 0.001). In 27 (79%) of the 34 patients there was a decrease in MIBG accumulation, in 18 (53%) an alteration in the circadian BP pattern and/or an increase in systolic and/or diastolic BP loads at night, and in 17 (50%) left ventricular hypertrophy and/or diastolic dysfunction. Twenty-two patients were symptomatic and had a mean EMG score of 37.7 +/- 25% (group I). The remaining 12 were asymptomatic and without neurological involvement (group II). Group I was characterized by older age (48 +/- 15 vs. 33 +/- 10.2 years, p = 0.01), lower MIBG uptake (1.5 +/- 0.4 vs. 2.2 +/- 0.5, p = 0.001), higher systolic (129 +/- 16 vs. 119 +/- 6 mmHg, p = 0.01) and diastolic daytime BP (82 +/- 10 vs. 76 +/- 6 mmHg, p = 0.05), and higher systolic (119 +/- 17 vs. 105 +/- 7 mmHg, p = 0.01) and diastolic nocturnal BP (71 +/- 11 vs. 62 +/- 9 mmHg, p = 0.01) than patients in group II. In 21/22 patients in group I and in 6/12 in group II there was a decrease in cardiac MIBG activity. Sixteen patients in group I and 2 in group II had abnormal circadian BP pattern. Left ventricular hypertrophy was only seen in group I.

CONCLUSIONS

Patients with FAP have a high incidence of cardiac denervation and an abnormal circadian BP pattern. These alterations in cardiac autonomic function precede the development of clinical manifestations and may be an important factor in determining the optimal timing for liver transplantation, which is currently the only way to control the progression of the disease.

Novel 3+1 mixed-ligand Technetium-99m complexes carrying dipeptides as monodentate ligands

Novel mixed ligand oxotechnetium complexes of the type [99mTcO(SSS)(SR)], in which the SR monodentate ligand is derived from dipeptides gly-gly, phe-gly and ala-gly, have been synthesized. These complexes, which have a molecular weight above 300, a lipophilic moiety, [TcO(SSS)]+, and an ionizable group separated from the lipophilic moiety by a spacer, have been obtained in 70-95% radiochemical yield. These compounds were prepared using 99mTc-tartrate as the precursor and Sn2+ as the reducing agent. The identity of the [99mTcO(SSS)(SR)] complexes has been established by HPLC comparison with the analogous oxorhenium complexes. The nature of the monodentate co-ligand strongly affects the stability of the 99mTc-complexes and their biodistribution. Complex 3b is the most stable in vitro presenting the highest blood clearance, a high liver uptake and a selective hepatobiliary excretion (54.5% ID at 15 min post-injection, and 69.3% ID at 60 min post injection). The results obtained show that 3b have reasonable stability and in vivo properties that may be useful for peptide labeling.

A new bis(3-hydroxy-4-pyridinone)-IDA derivative as a potential therapeutic chelating agent. Synthesis, metal-complexation and biological assays

A new bis(3-hydroxy-4-pyridinone) derivative of iminodiacetic acid, imino-bis(acetyl(1-(3'-aminopropyl)-3-hydroxy-2-methyl-4-pyridinone)), IDAPr(3,4-HP)(2), has been prepared and studied in its interaction with a set of hard metal ions. This tetradentate ligand presents a much higher chelating efficiency for trivalent hard metal ions (Fe, Ga, Al) than the monodentate derivative Deferriprone, namely at the diluted conditions prevailing in physiological conditions and at low clinical doses. A similar behaviour was also observed for the complexation with Zn(II) but at a significantly lower extent. This compound presents a moderate hydrophilic character at physiological pH (logD=-1.72). In vivo assays showed much more rapid clearance of (67)Ga from most tissues of metal-loaded mice than the drug Deferriprone and the radioactivity excretion occurs mostly through the kidneys. Therefore, results from in vitro and in vivo studies indicated good perspectives for this compound to be a potential decorporating agent for hard metal ions in overload situations without depletion of essential metal ions such as zinc.

N-Carboxyalkyl derivatives of 3-hydroxy-4-pyridinones: synthesis, complexation with Fe(III), Al(III) and Ga(III) and in vivo evaluation

A set of three N-carboxyalkyl 3-hydroxy-4-pyridinones has been studied as bidentate M(III) chelators (M=Fe, Al, Ga), with potential for oral administration. After preparation of the ligands, their protonation constants (log K(i)) and the stability constants of their metal complexes have been determined. The distribution coefficients of these compounds, between 1-octanol and Tris buffer pH 7.4, were measured. The effect of these compounds on the biodistribution of 67Ga-citrate loaded rats was investigated and compared with that of the administered 67Ga-complexes. Results indicated that, among these chelating agents, the N-carboxyethyl derivative has the highest affinity towards this set of metal ions, irrespective of the metal, and that it could even compete with transferrin, the main Fe-plasma protein. The binding affinity and the hydrophilic character decrease with the increase in the size of the alkylic chain. The biological assays indicate that the complex formation in vivo is characterized by a high kinetics and thermodynamic stability, suggesting a competition with the transferrin. All the ligands were found to enhance the excretion of the gallium. Noteworthy is the observed Ga bone fixation, mostly with the ethyl derivative, thus suggesting the potential use of the complex as a bone seeking agent.

Myocardial perfusion and angioplasty. Comparison of myocardial contrast echocardiography and scintigraphy

OBJECTIVES

To estimate the efficacy of myocardial contrast echocardiography (MCE) by harmonic power imaging (HPI), in evaluation of perfusion in one-vessel coronary disease treated by angioplasty, using myocardial scintigraphy as gold standard.

STUDY DESIGN

Prospective comparative study.

SETTING

Ambulatory.

POPULATION

We included 33 patients (pts), aged 53.5 +/- 9 years, 27 male.

INCLUSION CRITERIA

pts with one-vessel coronary disease (> or = 70% stenosis), with indication for angioplasty; sinus rhythm; good echocardiographic window with harmonic imaging. Exclusion criterion: previous myocardial infarction.

METHODS

All patients underwent myocardial scintigraphy and HPI together with stress echocardiography, both followed by angioplasty (stenting in ten). HPI and myocardial scintigraphy were repeated, in all patients, at three months after intervention. Ten patients were re-assessed by coronary angiography for ischemia on the scintigraphic study. For the HPI exam, Levovist was selected as contrast and dipyridamole as stress agent (0.56 mg/kg). Perfusion was assessed visually and classified by HPI and scintigraphy studies as: 1 (normal), 2 (reduced), or 3 (absent). For analysis, the left ventricle was divided into 16 segments.

RESULTS

Of the 43 coronary angiograms performed (ten at three months after angioplasty), 38 showed 70% stenosis, none occlusive or subocclusive. We analyzed 1056 left ventricle segments, from 66 HPI and myocardial scintigraphy studies (before and after angioplasty). Analysis was impossible or doubtful in 4.9%. Baseline and stress HPI detected 216 perfusion abnormalities. Global concordance between the segmental perfusion score obtained by HPI and scintigraphy was 66.2%, which became 76.3% when two groups were considered: a) score 1 b) score 2 and 3 together. In comparison with scintigraphy, HPI sensitivity for detection of perfusion abnormalities was 79.3% (higher for anterior septum, anterior and lateral wall) and specificity was 91.4% (higher for septum, inferior wall and apical segments). HPI correctly identified the location of coronary stenosis in 73.5% of patients.

CONCLUSIONS

In our study, HPI was a feasible and promising method for assessment of perfusion in one-vessel coronary disease and chronic ischemia. In comparison with myocardial scintigraphy, a high concordance for perfusion score was found, as well as high sensitivity and specificity for detection of perfusion abnormalities.

Synthesis, chelating properties towards gallium and biological evaluation of two N-substituted 3-hydroxy-4-pyridinones

Two N-substituted 3-hydroxy-4-pyridinones (1-(3'-aminopropyl)-3-hydroxy-2-methyl-4-pyridinone (L1) and 1-(2'-carboxyethyl)-3-hydroxy-2-methyl-4-pyridinone (L2)) were prepared through one- and three-step reactions, respectively. The pKa values of the ligands and the stability constants of their Ga(III) complexes have been determined. Both the complexes are strongly coordinated to three (O,O) hydroxypyridonate moieties. There is a clear effect of the N-substituents in the lipophilic-hydrophilic balance and in the Ga(III) binding interaction; the acid derivative (L2) has lower lipophilicity but higher chelating strength than the amine derivative (L1). Both chelators are shown to interfere in the typical biological behavior of 67Ga-citrate in mice: L1 enhanced the urinary excretion leading to an increased 67Ga removal from the soft tissue, while L2 induced a lower blood clearance with a pronounced bone uptake mainly at 48 h after injection, thus suggesting that the 67Ga-L2 complex could have potential interest as a bone imaging agent.

Role of myocardial ischemia and left ventricular wall motion abnormalities as contributory factors in the genesis of exercise-induced ST-segment elevation in Q-wave myocardial infarction

In patients with a previous myocardial infarction, controversy exists regarding the significance of postexercise ST-segment elevation in the infarct-related leads. Although usually admitted to be a sign of left ventricular dysfunction or myocardial aneurysm, other studies however have related this finding to transient myocardial ischemia and to the presence of jeopardized but viable myocardium in the infarct area. The aim of the present study was to assess the significance of postexercise ST-segment elevation in Q-wave leads as a marker of transmural ischemia or left ventricular dysfunction in 36 consecutive patients, 16 with exercise-induced ST-segment elevation in infarct-related leads. Patients were evaluated by treadmill exercise testing, coronary angiography and ventriculography, thallium-201 tomographic scintigraphy and radionuclide ventriculography within 3 months of the first myocardial infarction. Sixteen patients (group I) had exercise-induced ST segment elevation and 20 (group II) postexercise inversion, no change or pseudonormalization of the T wave in infarct-related leads. The study showed no difference in infarct-related artery, vessel disease or luminal diameter stenosis in groups I and II. The overall agreement between ST shifts and myocardial perfusion in the infarct area was 30.56% with a kappa coefficient of -0.33 (p = NS). The overall agreement between ST shifts and wall motion abnormalities was 69.44% with a kappa coefficient of 0.39 (p < 0.01), stress-induced ST-segment elevation being associated with severe wall contractile disorders in 85% of the patients. In conclusion stress-induced ST-segment elevation in Q wave leads, although not a marker of wall motion abnormalities, is associated with akinesia or dyskinesia of the left ventricular wall.

Post-exercise electrocardiographic alterations, ST-segment elevation and QTc changes in patients with recent myocardial infarction

Stress-induced ST-segment elevation and a prolongation or no change of the QTc ratio (corrected QT interval for heart rate) at maximal exercise in the infarct leads have been associated with the presence of residual myocardial ischemia in the infarct zone. The aim of this study was to test the agreement between stress-induced ST-segment elevation and post-exercise QTc changes in infarct leads, in 36 consecutive patients, studied by coronariography, radionuclide ventriculography and thallium-201 scintigraphy, within 3 months of the acute myocardial infarction. Sixteen patients (Group I) had exercise-induced ST-segment elevation in the infarct leads and 20 did not (Group II). The study showed no significant difference between severity of vessel disease and occlusion, prevalence of the infarct related artery or left ventricular dysfunction in Group I and II. No agreement between ST-segment shifts and myocardial perfusion in the infarct zone was found. Resting wall motion abnormalities were more severe in Group I than in Group II (p < 0.01). In the total of the 36 patients there was no agreement between ST-segment shifts and QTc-variations. The study showed agreement between QTc changes and myocardial perfusion in the infarct area (K = 0.64) (p < 0.001).

CONCLUSION

This study showed no relation between post-exercise ST elevation and post-exercise QTc variations in Q wave leads. QTc variations at the end of exercise in the infarct related leads identified residual ischemia. Exercise ST segment elevation, although not a marker of ischemia, is associated with more severe wall motion abnormalities in the infarct zone.

Human polyclonal immunoglobulin labelled with technetium-99m via NHS-MAG3: a comparison of radiochemical behavior and biological efficacy with other labelling methods

The aim of this study was to evaluate the radiochemical behavior, biological distribution, and localization in infection sites in mice of a human polyclonal immunoglobulin (HIG) labelled with 99mTc by a novel MAG3-labelling method. The resulting [99mTc]MAG3-HIG was compared with [99mTc]HIG preparations radiolabelled directly via 2-mercaptoethanol (2-Me) or stannous ion (Sn) reduction and indirectly via 2-iminothiolane (2-Im) conjugation. All preparations showed similar UV and radioactivity HPLC profile to that of native HIG except for 2-Im-HIG, which showed aggregates. The stabilities of the label to challenge with cysteine were similar for all the preparations. By nondenaturing SDS-PAGE, all preparations other than MAG3-HIG showed evidence of lower molecular weight fragments. The tissue distribution 4 and 24 h after intravenous administration of the four preparations were compared in mice previously administered with an isolate of Staphylococcus aureus in one thigh. The pharmacokinetics varied among the different preparations. When prepared via 2-Me, Sn, and 2-Im, both blood clearance and urinary excretion were faster than that of labelled MAG3-HIG. The absolute uptake in the infected thigh at 24 h was significantly higher for HIG labelled via MAG3 and 2-Me vs. the remaining methods. The infected thigh/normal thigh radioactivity ratios were similar at both time points for labelled HIG prepared via 2-Me, 2-Im, and NHS-MAG, methods but was significantly lower at 24 h for HIG prepared via Sn. The radioactive HPLC profiles of serum at 4 and 24 h were similar to that of the radiolabelled injectates. Based on these data we conclude that each radiolabelled HIG preparation studied showed increased localization in infectious foci although [99Tc]MAG3-HIG showed superior radiochemical and biological characteristics under the conditions of this investigation.

Technetium-99m labelling of the IOR CEA 1 monoclonal antibody: evaluation of different methods

AIM

The aim of this study was to investigate the in vivo and in vitro properties of 99mTc labelled monoclonal antibody, IOR CEA 1 when radiolabelled by different methods.

METHODS

To achieve that purpose IOR CEA was directly radiolabelled via 2-mercaptoethanol (2-Me) and stannous ion (SnCl2) reduction and indirectly via the 2-iminothiolane (2-Im) conjugation. The resulting 99mTc-MoAbs were analysed for number of free sulfhydryl groups, chemical and radiochemical purity (checked by HPLC and SDS PAGE), immunoreactivity and biological distribution in mice.

RESULTS

Experimental results indicated a similar radiochemical purity and immunoreactivity for direct labelling methods and a decrease of both for 2-Im method. 2-Me antibody reduction led to a high antibody fragmentation as indicated by non-denaturing SDS PAGE analysis. Nevertheless SnCl2 and 2-Im labels revealed lower in vivo stability.

CONCLUSION

99mTc-(2-Me) IOR CEA presented favorable in vitro and in vivo properties. Therefore this label was compared to 99mTc-monoclonal antibody BW 431/26. Similar characteristics were found. Clinical studies also revealed identical biodistribution profile.

[Coronary artery disease, myocardial perfusion and ventricular function in Q-wave and non-Q-wave myocardial infarcts]

Controversy remains in considering non-Q wave myocardial infarction (NQMI) a distinct pathophysiological entity of Q wave myocardial infarction (QMI). In order to analyze the severity of coronary artery disease, extension of myocardial scar or myocardial ischemia and ventricular function, 78 consecutive patients with QMI and 32 with NQMI, mean age 55.4 +/- 8.5, not submitted to thrombolytic therapy, were studied. Coronary angiography, exercise thallium scintigraphy and radionuclide ventriculography were performed in all at least within 3 months of a prior myocardial infarction. In the present study the occurrence of QMI was significantly more frequent in older patients than NQMI. There was no prevalence of occlusion either in the right, left circumflex or left anterior descending coronary arteries in both groups. Ejection fraction, degree of occlusion and presence of collateral circulation showed an equal prevalence in QMI and NQMI patients. A higher incidence of multivessel disease was found in NQMI that had less necrosis than QMI patients. The prevalence of exercise induced thallium-201 redistribution defects within the infarct zone was substantially higher and involved more scar segments in NQMI patients. Physiological and clinical consequences of coronary thrombosis depends on the size and the number of diseased arteries, the approach the pathophysiologic consequences of coronary disease in terms of fractal structure has been suggested. A pronounced heterogeneity in regional myocardial blood flow in a fractal branching arterial network may be responsible for the pathophysiologic differences of coronary thrombosis between Q-wave and non Q-wave infarction.

Comparison between dobutamine echocardiography and thallium-201 scintigraphy in detecting residual stenosis, ischemia, and necrosis in patients with prior myocardial infarction

BACKGROUND

Following the first attempts to detect myocardial ischemia with two-dimensional echocardiography stress testing, pharmacologic stress using dobutamine infusion has become an alternative to echocardiography exercise testing for evaluation of coronary artery disease. It has been shown that stress echocardiography has a diagnostic accuracy similar to that of an exercise thallium test. Other studies, however, indicated that radionuclide myocardial perfusion imaging was more sensitive than exercise or pharmacologic stress echocardiography for detection of ischemia or jeopardized myocardium.

HYPOTHESIS

The aim of the present study was to determine the ability of dobutamine stress echocardiography in comparison with thallium-201 scintigraphy to identify multivessel disease and the presence of myocardial scar and ischemia in 60 consecutive patients who suffered a first myocardial infarction (MI).

METHODS

Patients were evaluated by coronary angiography and ventriculography, thallium-201 (201TI) tomographic scintigraphy, and dobutamine echocardiography within 3 months of a first MI. Forty-seven had Q-wave MI and 13 had non-Q-wave MI. Eleven patients were excluded from final analysis-7 because of failure to achieve target heart rate in spite of the use of atropine, and 4 because of high blood pressure following the infusion of dobutamine.

RESULTS

Dobutamine echocardiography showed an overall sensitivity of 43% for detection of coronary artery lesions of 50-74% diameter stenosis and 201TI scintigraphy showed a sensitivity of 71%. For detection of lesions of > or = 75% diameter stenosis, dobutamine echocardiography showed a sensitivity of 52% and 201TI a sensitivity of 70%. Overall agreement between wall motion and myocardial perfusion for detection of necrosis and/or ischemia in the infarct area was 40.4% with a kappa coefficient of 0.09 (p = 0.13). For detection of ischemic myocardium outside the infarct zone, overall agreement was 78.6% with a kappa coefficient of 0.49 (p < 0.0001).

CONCLUSION

Dobutamine echocardiography results showed a lower sensitivity than myocardial perfusion images in predicting multivessel coronary artery disease, and there was poor agreement between both methods in identifying necrosis or ischemia.

Technetium-99m tetrofosmin rest/stress myocardial SPET with a same-day 2-hour protocol: comparison with coronary angiography. A Spanish-Portuguese multicentre clinical trial

Technetium-99m tetrofosmin (Myoview) has unique properties for myocardial perfusion imaging very early after injection of the tracer. We used a very short same-day rest/stress protocol, to be performed within 2 h and evaluated its diagnostic accuracy. The study included 144 patients from seven Spanish and four Portuguese centres with a diagnosis of uncomplicated coronary artery disease (CAD); 78 patients (54%) had no history of prior myocardial infarction. Patients were injected with </=300 MBq 99mTc-tetrofosmin at rest and </=900 MBq approximately 1 h later at peak exercise. Single-photon emission tomographic (SPET) acquisitions were initiated within 5-30 min post injection. The results were compared with those of coronary angiography (CA). The data of 142 patients were completely evaluable (two with non-evaluable images were excluded). The quality of rest images was excellent or good in 86%, regionally problematic in 7%, poor but well interpretable in 5% and non-evaluable in 2%. The overall sensitivity for the detection of CAD was 93%, the specificity 38% and the accuracy 85%. The localization of defects by SPET in relation to the perfusion territories of stenosed vessels (>/=50%) was achieved with a sensitivity of 64% for the left anterior descending artery, 49% for the left circumflex artery and 86% for the right coronary artery, and an accuracy of 71%, 72% and 73% respectively. Concordance of SPET and CA was 62% for single-vessel disease and 68% for multivessel disease. In conclusion, this Spanish-Portuguese multicentre clinical trial confirmed, in a considerable number of patients who underwent coronary angiography, the feasibility of 99mTc tetrofosmin (Myoview) rest/stress myocardial SPET using a very short protocol (2 h).

Wall motion abnormalities and late ventricular arrhythmia during the predischarge phase of acute myocardial infarction

BACKGROUND

Left ventricular wall aneurysm is a complication of acute myocardial infarction which has been considered a precipitating factor of cardiac failure and ventricular arrhythmia. We have evaluated the relation between severe left ventricular wall motion abnormalities and ventricular arrhythmia.

METHODS

During a two-year period 146 patients admitted to a coronary care unit with acute myocardial infarction were studied. Radionuclide angiography performed within the second and the fourth weeks was used to analyse phase and wall motility changes, and patients were divided into three groups: 1) Hypokinesia and/or akinesia localized to one segment: with no or slight changes in phase image--102 patients; 2) Aneurysm: left ventricular deformity with well-defined chromatic changes in phase image--19 patients; and 3) Dyskinesia and/or extensive akinesia of two or more segments: phase image with diffuse heterogeneous changes--25 patients. Ventricular arrhythmia was studied using Holter electrocardiography taken during the second week of acute myocardial infarction. Three rhythmic profiles were considered: no premature ventricular contractions--41 patients; with three or more than three premature ventricular contractions per hour--38 patients; repetitive premature ventricular contractions--20 patients.

RESULTS

Premature ventricular contractions were absent in 31 (30%) of the patients with hypokinesia/localized akinesia vs 8 (42%) of the patients with aneurysm, and vs 2 (8%) of the patients with dyskinesia/extensive akinesia. Premature ventricular contractions were frequent (> or = 3/h) in 22 (22%) of the patients with hypokinesia/localized akinesia vs 4 (21%) of the patients with aneurysm (p = 0.35; NS), and vs 12 (48%) of the patients with dyskinesia/extensive akinesia (p=0.003). Repetitive premature ventricular contractions were present in 10 (10%) of the patients with hypokinesia/localized akinesia vs 2 (11%) of the patients with aneurysm, and vs 8 (32%) of the patients with dyskinesia/extensive akinesia (p=0.008).

CONCLUSIONS

We conclude that the presence of aneurysm was not associated with a higher occurrence of ventricular arrhythmia, but patients with dyskinesia/extensive akinesia had a higher occurrence of ventricular arrhythmia, > or = 3 premature ventricular contractions per hour and repetitive premature ventricular contractions. Our results suggest that ventricular arrhythmia is related to functionally severe wall motion abnormalities, and not to anatomical discriminants. This finding leads us to suggest different electrophysiological mechanisms behind these two entities.

Minimal residual coronary obstructions in patients who suffered a first myocardial infarction. A prospective study comparing coronary angiography and exercise thallium scintigraphy

The purpose of the present study was to correlate the presence of minimal coronary obstruction (< or = 50%) assessed by coronary angiography with the presence of myocardial scar and ischemia detected by thallium-201 myocardial perfusion imaging. The study included 83 consecutive patients (74 men and 9 women) with a mean age 55.4 +/- 8.5 years who suffered a first myocardial infarction and did not undergo thrombolytic therapy. In all patients, coronary angiography, left ventriculography, and exercise thallium-201 tomographic scintigraphy were performed within 3 to 5 months of the myocardial infarction. Coronary arteriograms showed minimal residual obstructions in 37 (45%) patients. Of a total of 54 patients with < or = 50% obstruction, 18 showed persistent defects and 22 reversible defects on thallium scintigrams. The present study showing estimated angiographic stenosis of < or = 50% as being responsible either for myocardial scar or myocardial ischemia on postexercise thallium scintigrams leads us to conclude that percent value of stenosis does not accurately predict the pathophysiologic significance of coronary atherosclerotic lesions in patients who suffer a myocardial infarction. After a first myocardial infarction, coronary angiographies and thallium-201 scintigrams are complementary for an optimal treatment strategy for selected subsets of patients.

Postexercise changes of the QTc interval in patients with recent myocardial infarction

A lack of the QTc ratio decrease at maximal exercise is considered as an index of exercise-induced ischemia in patients with coronary artery disease. The authors studied 51 patients with recent myocardial infarction in order to evaluate the QTc changes with exercise in assessing the presence of remaining ischemic myocardium. All patients were submitted to exercise stress tests, coronary angiographies, and exercise thallium 201 scintigraphies within 3-5 months of the myocardial infarction. Of the patients studied, 18 showed one-vessel disease and 33 showed multivessel disease. All vessels were classified as patent or occluded. In all patients with reversible thallium 201 defects both at distance and in the infarct zone, the QTc interval following exercise either showed a prolongation or no change from the resting electrocardiogram. In patients with only fixed perfusion defects, the QTc shortened at the end of the test. This study showed a low sensitivity and specificity for inducible ST-segment depression compared with the delayed redistribution on the postexercise thallium 201 scintigram. QTc variations at the end of exercise electrocardiograms are valuable as a noninvasive, low-cost identification of residual ischemic myocardium in patients after myocardial infarction.

[Significance exercise-induced ST elevation in patients with myocardial infarction]

In 52 patients with previous myocardial infraction, 49 men and 3 women (mean age 56 +/- 7.1 years) the significance of ST-segment elevation during the stress-test, was evaluated. Of the 52 patients 15 (29%) showed St-segment elevation and 37(71%), showed no alteration of the ST-segment. Extension of coronary disease, degree of obstruction, wall motion abnormalities and the presence of residual ischemia were evaluated by coronary angiography, technetium-99M pyrophosphate imaging and exercise TL-201 scintigraphy. From the results of the study one may conclude that, in patients with previous myocardial infraction exercise, ST-segment elevation is a consequence of sub-occlusion of the left anterior descending coronary artery with severe ventricular dysfunction either in patients with one or multiple vessel disease.

Transient Crossed Aphasia: a Case Study with SPECT

A 45-year-old right-handed man developed "crossed" anomie aphasia, neglect and inaccurate reaching of his left arm in both hemispaces due to a right parietal haemorrhage. Aphasia cleared in a few days. SPECT failed to demonstrate crossed left hemispheric diaschisis. This report emphasizes the importance of evaluating patients in the acute stage and of coupling "static" and "functional" imaging methods when studying brain-behavior relationships.

[Equilibrium radionuclide angiography in patients with previous myocardial infarct. Correlation with electrocardiogram and coronarography]

Fifty five patients with previous myocardial infarction (MI), 47 male and 8 female, mean age 55.5 +/- 8.9 years, have been studied in order to correlate the alterations found on the equilibrium (gated) radionuclide angiogram (RNA) with the location of the MI on the electrocardiogram of the obstructive lesions on coronary angiographies. Of the 55 patients studied, 22% showed no regional wall motion abnormalities (WMA). Both MI with and without Q wave may show WMA, which are significatively more frequent in patients with anterior MI on the ECG and with occlusive lesions (greater than 90%) on coronariographies. Regional localization of the WMA on the RNA does not identify the localization of the obstructive lesions. Hypokinesia was the most frequent type of WMA found both with occlusive (greater than 90%) and sub-occlusive (greater than 75%) lesions. Low values of the ejection fraction (less than 45%) were found in the presence of WMA and occlusive artery lesions.

[Surgical treatment of variant angina. Apropos of a clinical case]

A case of a male 66 years-old patient who presented with a clinical picture of Prinzmetal's variant angina early in the evolution of an acute myocardial infarction is reported. Transient elevation of ST-segment was documented on Holter monitoring in association with angina at rest as well as asymptomatic episodes of ST-segment changes. Significant two-vessels obstructive lesions (left anterior descending and circumflex arteries) was present. As variant angina had several recurrences in spite of medical therapy with nitrates and calcium antagonists, the patient was submitted to coronary by-pass surgery associated to plexectomy. A Thallium myocardial scintigraphy suggests that a peroperative infarction had occurred. The patient was asymptomatic at six months follow-up.

[Comparison of Holter electrocardiography and thallium 201 scintigraphy in the detection of myocardial ischemia]

OBJECTIVE OF THE STUDY

To compare ischemic changes (I) detected by Holter ECG (H ECG) to the myocardial perfusion defects found in 201 TI myocardial perfusion scintigraphy.

DESIGN

201 TI exercise test was made during the performance of a 24 hours H ECG. The validation of ST segment changes detected by H ECG during the exercise test was made on basis of reversible myocardial perfusion defects (RPD) detected on 201 TL and a relation between ST segment changes detected during the remaining 24 hours recording period and 201 TI (TI) RPD was established.

SETTING

The patients (pt) included in the study have come from Cardiology and Heart Surgery Clinics of a Central teaching hospital.

MATERIAL AND METHODS

20 pt with a high coronary artery disease prevalence have been submitted to a two lead (V5 and aVF) 24 hour H ECG during which they have performed a symptom limited bicycle exercise test followed by an injection of 201 TI with acquisition 5 minutes later. Ischemic episodes detected on H ECG were quantified and their relation with heart rate and symptoms was established. As far as 201 TI studies are concerned the fixed and reversible perfusion defects as well as their location were evaluated.

RESULTS

1. H ECG: 6 pt (30%) presented ST changes on H ECG during the exercise test and a total of 9 pt (45%) had ST changes during exercise and during the remaining period of H ECG. 2. TI: 19 pt presented perfusion defects images (fixed in 7, reversible in 14, both kinds of defects in 7). 3. H ECG validation: H ECG during exercise presented I in 6 out of 14 pt with RPD on TI (sensitivity = 43%). Six of these 8 pt, with negative H and positive TI, had a chronic myocardial infarction. All the 6 pt with negative TI had negative H ECG (specificity = 100%). 4. H ECG TI comparison: 7 (50%) of the 14 pt with RPD had ST changes on 24 hrs H ECG. Seven of 11 pt with negative H ECG had RPD in TI. Two pt with negative TI had positive H ECG. These 2 pt had during H ECG a higher heart rate (HR) than the HR recorded during the exercise test.

CONCLUSIONS

1. In pt with known CAD, TI has a high sensitivity and specificity to show perfusion defects. 2. Considering TI as gold standard, H ECG showed to be a useful method to detect I in the studied population (sens. = 43%; spec. = 100%). 3. H ECG revealed to be an important diagnostic tool in detecting additional I episodes beyond the ones recorded during TI exercise test.

[Early left ventricular dysfunction in acute myocardial infarct. Evaluation using imaging methods]

A patient admitted in a Coronary Care Unit with an acute anterior myocardial infarction, is presented. He had initially normal left ventricular function and, on the 11th day he had, suddenly, an acute pulmonary edema. The reason for this episode was detected through imaging techniques--echocardiography and isotopic studies, and consisted on infarct expansion with early evolution for apical aneurysm. Contrast angiography confirmed the presence of a huge aneurysm and two vessels disease. Tallium Scintigraphy showed reversible ischemia beyond necrotic areas. The patient was submitted to aneurysmectomy and received three aorto-coronary bypass. He is now doing well, in class I, NYHA. The discussion emphasizes the actual role of imaging techniques in the diagnosis of infarct expansion and early functional aneurysm. We discuss the prognostic of infarct expansion and the importance of perfusion studies on defining areas of myocardium in jeopardy, enabling a better surgical approach.