Endovascular treatment for cerebral venous sinus thrombosis - a single center study.

BACKGROUND: Cerebral venous sinus thrombosis (CVST) is a rare cerebrovascular disorder. The majority of these patients respond favorably to systemic anticoagulation. However, a subset of patients will deteriorate clinically, despite optimal medical therapy. METHODS: Retrospective single center study of 28 consecutive CVST patients treated with systemic anticoagulation and additional endovascular therapy. RESULTS: Median age was 37.5 years (range 15-76 years), there were 21 (75%) women, and 20 (71%) had thrombosis involving ≥2 venous sinuses. Intracranial hemorrhage (ICH) was present at admission in 18 patients (64%). Endovascular therapy consisted of local thrombolysis in 26 (93%) patients; 9 patients (32%) had additional mechanical thrombectomy, and in 2 (7%) patients thrombectomy alone was performed. Complete recanalization at end of the final intervention was achieved in 15 patients (54%), partial recanalization in 11 patients (39%), whereas there was no recanalization in 2 patients (7%). On follow-up imaging, conducted between 3 and 6 months, recanalization further improved to 76%, 19% and 5%, respectively. A favorable outcome (mRS ≤ 2) was achieved in 63% of patients at 3 months, which improved to 79% at 6 months. Post-procedural ICH or volume expansion of preexisting ICH was seen in 9 patients (32%). In total 5 patients died (18%). CONCLUSIONS: Systemic anticoagulation with the addition of endovascular therapy with local thrombolysis and/or mechanical thrombectomy is a potential strategy to obtain recanalization in patients with CVST who deteriorate clinically despite medical therapy or are comatose. Endovascular therapy may increase the risk of ICH.

Carotid Stenosis Assessment with Vector Concentration before and after Stenting.

Digital subtraction angiography (DSA) is considered the reference method for the assessment of carotid artery stenosis; however, the procedure is invasive and accompanied by ionizing radiation. Velocity estimation with duplex ultrasound (DUS) is widely used for carotid artery stenosis assessment since no radiation or intravenous contrast is required; however, the method is angle-dependent. Vector concentration (VC) is a parameter for flow complexity assessment derived from the angle independent ultrasound method vector flow imaging (VFI), and VC has shown to correlate strongly with stenosis degree. The aim of this study was to compare VC estimates and DUS estimated peak-systolic (PSV) and end-diastolic velocities (EDV) for carotid artery stenosis patients, with the stenosis degree obtained with DSA. Eleven patients with symptomatic carotid artery stenosis were examined with DUS, VFI, and DSA before and after stent treatment. Compared to DSA, VC showed a strong correlation (r = -0.79, p < 0.001), while PSV (r = 0.68, p = 0.002) and EDV (r = 0.51, p = 0.048) obtained with DUS showed a moderate correlation. VFI using VC calculations may be a useful ultrasound method for carotid artery stenosis and stent patency assessment.

Early response evaluation of neoadjuvant therapy with PET/MRI to predict resectability in patients with adenocarcinoma of the esophagogastric junction.

STUDY DESIGN AND PURPOSE: Positron emission tomography (PET)/magnetic resonance imaging (MRI) is a new modality that has showed promising results for various clinical indications. Currently, evaluation of neoadjuvant therapy (NT) among patients with adenocarcinoma of the esophagogastric junction has primarily been reserved for PET/computed tomography. Our aim was to evaluate if early response evaluation by PET/MRI is a feasible method to predict resectability. METHODS AND MATERIALS: Patients with untreated adenocarcinoma of the esophagogastric junction (Siewert types I/II) and fit for NT with no contraindications for PET/MRI were considered eligible. A baseline scan was performed prior to NT induction and an evaluation scan 3 weeks later. For histopathological response evaluation, the Mandard tumor regression grade score was applied. Response on PET/MRI was evaluated with Response Evaluation Criteria in Solid Tumors (RECIST 1.1), and change in ADC and SUVmax values. RESULTS: Twenty-eight patients were enrolled, and 22 completed both scans and proceeded to final analyses. Seventeen patients were found resectable versus five who were found unresectable. PET/MRI response evaluation had a sensitivity 94%, specificity 80%, and AUC = 0.95 when predicting resectability in patients with adenocarcinoma of the esophagogastric junction. No association with histopathological response (tumor regression grade) was found nor was RECIST correlated with resectability. CONCLUSION: Response evaluation using PET/MRI was a feasible method to predict resectability in patients with adenocarcinoma of the esophagogastric junction in this pilot study. However, larger studies are warranted to justify the use of the modality for this indication.

Snaring of a Glued Microcatheter During Embolization of an Arteriovenous Malformation with N-Butyl Cyanoacrylate.

BACKGROUND: Microcatheter entrapment during embolization of brain arteriovenous malformations (AVMs) represents a potentially harmful technical complication. Although several techniques have been reported for endovascular catheter retrieval from an Onyx cast, such methods have never been demonstrated with acrylic glues. We report a case of removal of a glued microcatheter from an N-butyl cyanoacrylate (NBCA) cast using a microsnare. METHODS AND RESULTS: A 26-year-old woman presented with an intracranial hemorrhage resulting from a ruptured right choroidal AVM. A microcatheter used for transarterial embolization was unintentionally glued into the NBCA cast. Because attempts to remove the catheter by simple traction failed, a microsnare was used and allowed withdrawal of the entrapped microcatheter without causing damage to the cerebral vasculature. The patient woke up without clinical sequelae. CONCLUSIONS: Although it is not recommended as routine practice, snaring a glued microcatheter is feasible and can be used in selected cases as a last resort if thromboembolic complications are feared.

[Endovascular thrombectomy in ischaemic apoplexy treatment].

The goal when treating ischaemic apoplexy is a rapid, safe and effective recanalization. For some years, the main treatment has been the administration of IV thrombolysis, but due to several restrictions, lack of efficacy and a limited window of opportunity for treatment, an alternative method was needed. This formed the foundation for the develop-ment of endovascular thrombectomy. This review describes the development and the mechanisms involved as well as the results and treatment gains.

Combined hyperpolarized 13C-pyruvate MRS and 18F-FDG PET (hyperPET) estimates of glycolysis in canine cancer patients.

13C Magnetic Resonance Spectroscopy (MRS) using hyperpolarized 13C-labeled pyruvate as a substrate offers a measure of pyruvate-lactate interconversion and is thereby a marker of the elevated aerobic glycolysis (Warburg effect) generally exhibited by cancer cells. Here, we aim to compare hyperpolarized [1-13C]pyruvate MRS with simultaneous 18F-2-fluoro-2-deoxy-d-glucose (FDG) PET in a cross-sectional study of canine cancer patients. METHODS: Canine cancer patients underwent integrated PET/MRI using a clinical whole-body system. Hyperpolarized [1-13C]pyruvate was obtained using dissolution-DNP. 18F-FDG PET, dynamic 13C MRS, 13C MRS Imaging (MRSI) and anatomical 1H MRI was acquired from 17 patients. Apparent pyruvate-to-lactate rate constants were estimated from dynamic 13C MRS. 18F-FDG Standard Uptake Values and maximum [1-13C]lactate-to-total-13C ratios were obtained from tumor regions of interest. Following inspection of data, patients were grouped according to main cancer type and linear regression between measures of lactate generation and 18F-FDG uptake were tested within groups. Between groups, the same measures were tested for group differences. RESULTS: The main cancer types of the 17 patients were sarcoma (n = 11), carcinoma (n = 5) and mastocytoma (n = 1). Significant correlations between pyruvate-to-lactate rate constants and 18F-FDG uptake were found for sarcoma patients, whereas no significant correlations appeared for carcinoma patients. The sarcoma patients showed a non-significant trend towards lower 18F-FDG uptake and higher lactate generation than carcinoma patients. However, the ratio of lactate generation to 18F-FDG uptake was found to be significantly higher in sarcoma as compared to carcinoma. The results were found both when lactate generation was estimated as an apparent pyruvate-to-lactate rate constant from dynamic 13C MRS and as an [1-13C]lactate to total 13C ratio from 13C MRSI. CONCLUSIONS: A comparison of hyperpolarized [1-13C]pyruvate MRS with simultaneous 18F-FDG PET indicate that lactate generation and 18F-FDG uptake in cancers can be related and that their relation depend on cancer type. This finding could be important for the interpretation and eventual clinical implementation of hyperpolarized 13C. In addition, the differences between the two modalities may allow for better metabolic phenotyping performing hybrid imaging in the form of hyperPET.

Non-ECG-gated CT pulmonary angiography and the prediction of right ventricular dysfunction in patients suspected of pulmonary embolism.

PURPOSE: Right ventricular dysfunction (RVD) is an important prognostic factor of 30-day mortality in patients with acute pulmonary embolism (PE). The aim of our study was to evaluate whether non-electrocardiogram (ECG)-gated cardiovascular parameters attained during computed tomography pulmonary angiography (CTPA) could predict RVD in patients suspected of PE using ECG-gated cardiac CT angiography as reference. METHODS: Consecutive patients suspected of PE were referred to a ventilation/perfusion single-photon emission tomography (V/Q-SPECT) as first-line imaging procedure. Patients had a V/Q-SPECT/CT, a CTPA and an ECG-gated cardiac CT angiography performed the same day. RESULTS: A total of 71 patients were available for analysis. Seventeen patients (24%) had RVD. The non-ECG-gated dimensions of left and right ventricle and the major vessels were correlated with ECG-gated cardiac dimensions. The size of the pulmonary trunk could identify patients with RVD: AUC (0·67, 95% confidence intervals (CIs) 0·52-0·82) as seen in the ROC curve (P<0·05). With a cut-off value of the pulmonary trunk of 29 mm, the sensitivity and specificity were 70·6% and 55·5%, respectively. The positive predictive and negative predictive values for detection of RVD were 59·1% and 85·7%, respectively. CONCLUSION: In the present study, we demonstrated correlation between ECG-gated cardiac dimensions and non-ECG-gated cardiovascular parameters, however with only moderate diagnostic accuracies. We demonstrated that the dimension of the pulmonary trunk might be of value in detection of patients with RVD. We suggest further studies on the potential value of non-ECG-gated cardiac dimensions in patients suspected of PE.

The use of dynamic nuclear polarization (13)C-pyruvate MRS in cancer.

In recent years there has been an immense development of new targeted anti-cancer drugs. For practicing precision medicine, a sensitive method imaging for non-invasive, assessment of early treatment response and for assisting in developing new drugs is warranted. Magnetic Resonance Spectroscopy (MRS) is a potent technique for non-invasive in vivo investigation of tissue chemistry and cellular metabolism. Hyperpolarization by Dynamic Nuclear Polarization (DNP) is capable of creating solutions of molecules with polarized nuclear spins in a range of biological molecules and has enabled the real-time investigation of in vivo metabolism. The development of this new method has been demonstrated to enhance the nuclear polarization more than 10,000-fold, thereby significantly increasing the sensitivity of the MRS with a spatial resolution to the millimeters and a temporal resolution at the subsecond range. Furthermore, the method enables measuring kinetics of conversion of substrates into cell metabolites and can be integrated with anatomical proton magnetic resonance imaging (MRI). Many nuclei and substrates have been hyperpolarized using the DNP method. Currently, the most widely used compound is (13)C-pyruvate due to favoring technicalities. Intravenous injection of the hyperpolarized (13)C-pyruvate results in appearance of (13)C-lactate, (13)C-alanine and (13)C-bicarbonate resonance peaks depending on the tissue, disease and the metabolic state probed. In cancer, the lactate level is increased due to increased glycolysis. The use of DNP enhanced (13)C-pyruvate has in preclinical studies shown to be a sensitive method for detecting cancer and for assessment of early treatment response in a variety of cancers. Recently, a first-in-man 31-patient study was conducted with the primary objective to assess the safety of hyperpolarized (13)C-pyruvate in healthy subjects and prostate cancer patients. The study showed an elevated (13)C-lactate/(13)C-pyruvate ratio in regions of biopsy-proven prostate cancer compared to noncancerous tissue. However, more studies are needed in order to establish use of hyperpolarized (13)C MRS imaging of cancer.

Simultaneous Hyperpolarized 13C-Pyruvate MRI and 18F-FDG PET (HyperPET) in 10 Dogs with Cancer.

UNLABELLED: With the introduction of combined PET/MR spectroscopic (MRS) imaging, it is now possible to directly and indirectly image the Warburg effect with hyperpolarized (13)C-pyruvate and (18)F-FDG PET imaging, respectively, via a technique we have named hyperPET. The main purpose of this present study was to establish a practical workflow for performing (18)F-FDG PET and hyperpolarized (13)C-pyruvate MRS imaging simultaneously for tumor tissue characterization and on a larger scale test its feasibility. In addition, we evaluated the correlation between (18)F-FDG uptake and (13)C-lactate production. METHODS: Ten dogs with biopsy-verified spontaneous malignant tumors were included for imaging. All dogs underwent a protocol of simultaneous (18)F-FDG PET, anatomic MR, and hyperpolarized dynamic nuclear polarization with (13)C-pyruvate imaging. The data were acquired using a combined clinical PET/MR imaging scanner. RESULTS: We found that combined (18)F-FDG PET and (13)C-pyruvate MRS imaging was possible in a single session of approximately 2 h. A continuous workflow was obtained with the injection of (18)F-FDG when the dogs was placed in the PET/MR scanner. (13)C-MRS dynamic acquisition demonstrated in an axial slab increased (13)C-lactate production in 9 of 10 dogs. For the 9 dogs, the (13)C-lactate was detected after a mean of 25 s (range, 17-33 s), with a mean to peak of (13)C-lactate at 49 s (range, 40-62 s). (13)C-pyruvate could be detected on average after 13 s (range, 5-26 s) and peaked on average after 25 s (range, 13-42 s). We noticed concordance of (18)F-FDG uptake and production of (13)C-lactate in most, but not all, axial slices. CONCLUSION: In this study, we have shown in a series of dogs with cancer that hyperPET can easily be performed within 2 h. We showed mostly correspondence between (13)C-lactate production and (18)F-FDG uptake and expect the combined modalities to reveal additional metabolic information to improve prognostic value and improve response monitoring.

Simultaneous hyperpolarized (13)C-pyruvate MRI and (18)F-FDG-PET in cancer (hyperPET): feasibility of a new imaging concept using a clinical PET/MRI scanner.

In this paper we demonstrate, for the first time, the feasibility of a new imaging concept - combined hyperpolarized (13)C-pyruvate magnetic resonance spectroscopic imaging (MRSI) and (18)F-FDG-PET imaging. This procedure was performed in a clinical PET/MRI scanner with a canine cancer patient. We have named this concept hyper PET. Intravenous injection of the hyperpolarized (13)C-pyruvate results in an increase of (13)C-lactate, (13)C-alanine and (13)C-CO2 ((13)C-HCO3) resonance peaks relative to the tissue, disease and the metabolic state probed. Accordingly, with dynamic nuclear polarization (DNP) and use of (13)C-pyruvate it is now possible to directly study the Warburg Effect through the rate of conversion of (13)C-pyruvate to (13)C-lactate. In this study, we combined it with (18)F-FDG-PET that studies uptake of glucose in the cells. A canine cancer patient with a histology verified local recurrence of a liposarcoma on the right forepaw was imaged using a combined PET/MR clinical scanner. PET was performed as a single-bed, 10 min acquisition, 107 min post injection of 310 MBq (18)F-FDG. (13)C-chemical shift imaging (CSI) was performed just after FDG-PET and 30 s post injection of 23 mL hyperpolarized (13)C-pyruvate. Peak heights of (13)C-pyruvate and (13)C-lactate were quantified using a general linear model. Anatomic (1)H-MRI included axial and coronal T1 vibe, coronal T2-tse and axial T1-tse with fat saturation following gadolinium injection. In the tumor we found clearly increased (13)C-lactate production, which also corresponded to high (18)F-FDG uptake on PET. This is in agreement with the fact that glycolysis and production of lactate are increased in tumor cells compared to normal cells. Yet, most interestingly, also in the muscle of the forepaw of the dog high (18)F-FDG uptake was observed. This was due to activity in these muscles prior to anesthesia, which was not accompanied by a similarly high (13)C-lactate production. Accordingly, this clearly demonstrates how the Warburg Effect directly can be demonstrated by hyperpolarized (13)C-pyruvate MRSI. This was not possible with (18)F-FDG-PET imaging due to inability to discriminate between causes of increased glucose uptake. We propose that this new concept of simultaneous hyperpolarized (13)C-pyruvate MRSI and PET may be highly valuable for image-based non-invasive phenotyping of tumors. This methods may be useful for treatment planning and therapy monitoring.

In Vivo Phenotyping of Tumor Metabolism in a Canine Cancer Patient with Simultaneous (18)F-FDG-PET and Hyperpolarized (13)C-Pyruvate Magnetic Resonance Spectroscopic Imaging (hyperPET): Mismatch Demonstrates that FDG may not Always Reflect the Warburg Effect.

In this communication the mismatch between simultaneous (18)F-FDG-PET and a (13)C-lactate imaging (hyperPET) in a biopsy verified squamous cell carcinoma in the right tonsil of a canine cancer patient is shown. The results demonstrate that (18)F-FDG-PET may not always reflect the Warburg effect in all tumors.

SPECT/CT and pulmonary embolism.

Acute pulmonary embolism (PE) is diagnosed either by ventilation/perfusion (V/P) scintigraphy or pulmonary CT angiography (CTPA). In recent years both techniques have improved. Many nuclear medicine centres have adopted the single photon emission CT (SPECT) technique as opposed to the planar technique for diagnosing PE. SPECT has been shown to have fewer indeterminate results and a higher diagnostic value. The latest improvement is the combination of a low-dose CT scan with a V/P SPECT scan in a hybrid tomograph. In a study comparing CTPA, planar scintigraphy and SPECT alone, SPECT/CT had the best diagnostic accuracy for PE. In addition, recent developments in the CTPA technique have made it possible to image the pulmonary arteries of the lungs in one breath-hold. This development is based on the change from a single-detector to multidetector CT technology with an increase in volume coverage per rotation and faster rotation. Furthermore, the dual energy CT technique is a promising modality that can provide functional imaging in combination with anatomical information. Newer high-end CT scanners and SPECT systems are able to visualize smaller subsegmental emboli. However, consensus is lacking regarding the clinical impact and treatment. In the present review, SPECT and SPECT in combination with low-dose CT, CTPA and dual energy CT are discussed in the context of diagnosing PE.

Silent ischemic heart disease and pericardial fat volume in HIV-infected patients: a case-control myocardial perfusion scintigraphy study.

OBJECTIVES: to determine the prevalence of asymptomatic ischemic heart disease (IHD) in HIV patients by myocardial perfusion scintigraphy (MPS) and to determine the value of coronary artery calcium score (CACS), carotid intima-media thickness (cIMT) and pericardial fat volume as screening tools for detection of IHD in subjects with HIV. BACKGROUND: Patients with HIV seem prone to early development of IHD. METHODS: 105 consecutive HIV patients (mean age 47.4 years; mean duration of HIV 12.3 years; mean CD4+ cell count 636×106/L; all receiving antiretroviral therapy) and 105 controls matched for age, gender and smoking status, without history of IHD were recruited. MPS, CACS, cIMT, pericardial fat volume, and cardiovascular risk scores were measured. RESULTS: HIV patients demonstrated higher prevalence of perfusion defects than controls (18% vs. 0%; p<0.001) despite similar risk scores. Of HIV patients with perfusion defects, 42% had a CACS = 0. CACS and cIMT were similar in HIV patients and controls. HIV patients on average had 35% increased pericardial fat volume and increased concentration of biomarkers of atherosclerosis in the blood. HIV patients with myocardial perfusion defects had increased pericardial fat volume compared with HIV patients without perfusion defects (314±43 vs. 189±12 mL; p<0.001). CONCLUSIONS: HIV patients had an increased prevalence of silent IHD compared to controls as demonstrated by MPS. The finding was strongly associated with pericardial fat volume, whereas cardiovascular risk scores, cIMT and CACS seem less useful as screening tools for detection of myocardial perfusion defects in HIV patients.

[Glioblastoma multiforme with intra- and extramedullary dissemination to the spinal cord]. / Glioblastoma multiforme med intra- og ekstramedullær disseminering til spinalkanalen.

Metastases to the spinal cord from glioblastoma multiforme (GBM) are uncommon, but important to have in mind when patients with a history of GBM present with symptoms that do not correlate with the primary disease pattern. We report a rare case, where a male with GBM, six months after tumour excision followed by concomitant radio- and chemotherapy, presented with gait disturbance and unspecific neurological symptoms of the lower right limb. Magnetic resonance imaging of columna totalis revealed both intra- and extramedullary metastases in the spinal cord. The patient died one month later.

Changes in lung function of HIV-infected patients: a 4.5-year follow-up study.

OBJECTIVE: To investigate the development of lung function in HIV-infected patients. METHODS: In a prospective cohort study, 88 HIV-infected patients had a lung function test performed and 63 patients (72%) had their LFT repeated with a median follow-up period of 4.4 years. Forty-eight per cent were smokers, and at the re-examination, 97% were on combination antiretroviral therapy. RESULTS: Carbon monoxide diffusion capacity was reduced and decreased over time in both smokers and non-smokers. Alveolar volume decreased and forced vital capacity increased similarly in both smokers and non-smokers. No changes were observed in forced expiratory volume or peak flow, but smokers had reduced values compared with those of the non-smokers at both examinations. FEV1/FVC was reduced especially in smokers and declined in both smokers and non-smokers. CONCLUSIONS: Carbon monoxide diffusion capacity is reduced in HIV-infected patients and seems to decline over time. Additionally, signs of obstructive lung disease are present in HIV-infected patients and seem to increase over time, although only modestly.

[Combined ventilation/perfusion SPECT/CT is best for diagnosing pulmonary embolism]. / Kombineret ventilations/perfusions-SPECT/CT er bedst til diagnostik af lungeemboli.

The diagnosis of pulmonary embolism (PE) is usually established by a combination of clinical assessment, D-dimer test and imaging with either lung scintigraphy or pulmonary multidetector computed tomography angiography (CTA). Which of the two methods to use in PE diagnostic has not been determined and very limited data comparing these modalities are available. With the use of hybrid scanners, ventilation/perfusion-single-photon-emission-tomography (V/Q-SPECT) in combination with low-dose CT without contrast enhancement is feasible and should probably be considered first-line imaging in diagnosing PE.

Limited value of novel pulmonary embolism biomarkers in patients with coronary atherosclerosis.

BACKGROUND: Recent research supports the efficacy of various plasma biomarkers in diagnosing pulmonary embolism (PE) including E-selectin, MMP-9, MPO, sVCAM-1, sICAM-1, adiponectin, hs-CRP and tPAI-1. OBJECTIVE: We hypothesized that these biomarkers, which are affected in both venous and arterial thromboembolic diseases, have a limited potential of diagnosing PE in patients with concomitant coronary atherosclerosis, as assessed from a low-dose CT scan of the thorax, compared to patients without atherosclerosis. METHODS: Consecutive patients suspected of PE were referred. All patients had a ventilation/perfusion single photon emission tomography (V/Q-SPECT), low-dose pulmonary CT, pulmonary multidetector computer tomography angiography, blood samples and ECG-gated cardiac CT performed the same day. RESULTS: A total of 69 patients were included, of which 28 (41%) had PE. In patients without coronary calcium, MMP-9 and tPAI-1 were significantly elevated (P<0·042 and P<0·049) in patients diagnosed with PE. From the receiver operating curves, we chose a cut-off value for MMP-9 at 164·4 ng l(-1) , which yielded sensitivity, specificity, positive and negative predictive values of 63%, 78%, 71% and 70%, respectively. With a chosen cut-off value for tPAI-1 at 56·3 ng l(-1) , the sensitivity, specificity, positive and negative predictive values were 88%, 89%, 88% and 89%, respectively. In patients with coronary calcium, none of the biomarkers could discriminate between PE and no PE. CONCLUSION: Plasma levels of tPAI-1 and MMP-9 are potentially useful in patients suspected of PE, however, not in the presence of the coronary atherosclerosis.

Neuroendocrine activation and diagnostics in pulmonary embolism: Translational studies.

Acute pulmonary embolism (PE) is a severe and potentially fatal disease which acutely augments the right ventricle (RV) strain. Development of RV dysfunction (RVD) in the disease process is synonymous with an overall poor prognosis. The diagnosis of PE is usually established by a combination of clinical assessment, D-dimer test and medical imaging with either lung scintigraphy or pulmonary multidetector computer tomography (MDCT) angiography. Which of the two methods to use in PE diagnostic has not been determined and very limited data comparing these modalities are available. Assessment of RV function is cumbersome due to complex geometry. RVD is usually established by echocardiography which is observer dependent, has low reproducibility, and requires expertise. Therefore, a simple and reproducible biochemical method to assess RVD in patients with PE would be desirable. Brain natriuretic peptide (BNP), pro-atrial natriuretic peptide (pro-ANP), cardiac troponin I (TnI), and endothelin-1 (ET-1) have been the most studied plasma biomarkers in the context of risk stratification in PE. BNP is mainly produced in the ventricles of the heart. It is released from the left ventricle in response to increased filling pressure and is increased in chronic left heart failure. Pro-ANP is primarily produced in the atria, is released by atrial distention and is elevated in chronic pulmonary hypertension and could be an early marker for RVD. Plasma level of ET-1 has been shown to correlate with pulmonary pressure and is released from endothelial cells in the pulmonary vessels. Additionally, increases in circulating levels of ET-1 have been reported in an experimental animal model of PE. TnI is part of a complex of regulatory proteins in the cardiac myofilaments and is released upon myocyte injury. It is related to short term clinical outcome, prolonged hypotension, and cardiogenic shock after myocardial infarction and is a predictor of 30-day mortality and RVD using echocardiography in patients with PE. Our hypothesis was therefore that the neuroendocrine activation of BNP, pro-ANP, ET-1, and TnI alone or in combination could serve as markers of RVD in patients with PE. The use of plasma biomarkers would be much simpler than reproducible medical imaging methods such as magnetic resonance imaging (MRI), radionuclide based methods etc.

Reduction in coronary and peripheral vasomotor function in patients with HIV after initiation of antiretroviral therapy: a longitudinal study with positron emission tomography and flow-mediated dilation.

OBJECTIVES: The mechanisms underlying the increased cardiovascular risk in patients with HIV on antiretroviral therapy (ART) are not known. Our aim was to study the endothelial function of the coronary arteries by cardiac perfusion positron emission tomography (PET) in patients with HIV initiating ART. In addition, flow-mediated dilation (FMD) of the brachial artery was measured. METHODS: Patients with HIV scheduled to initiate ART (n=12) were included. NH3 perfusion PET and FMD scans were performed both before and 5 weeks (24-67 days) after initiation of ART. Data were compared with paired t-tests and a P value of less than 0.05 was considered significant. RESULTS: No changes were found in the pulse-pressure-corrected myocardial rest perfusion (1.22+/-0.07-1.09+/-0.05 ml/min/g tissue, NS) or cold pressor reserve (1.18+/-0.08-1.27+/-0.05, NS). However, the maximal myocardial perfusion decreased 31% from 2.50+/-0.25 to 1.73+/-0.15 ml/min/g tissue (P=0.009) and the myocardial perfusion reserve decreased 20% from 3.11+/-0.32 to 2.48+/-0.25 (P=0.042). FMD decreased from 8.68+/-1.70 to 4.58+/-0.93% (P=0.027). No change was observed in nitroglycerin-mediated dilation (12.8+/-1.0-14.4+/-1.4%, NS). CONCLUSION: In patients with HIV initiating ART, signs of development of endothelial dysfunction assessed by coronary perfusion PET and FMD were found early after starting medication.

ANP, BNP and D-dimer predict right ventricular dysfunction in patients with acute pulmonary embolism.

BACKGROUND: The aim of this study was to predict right ventricular dysfunction (RVD) using plasma concentration of D-dimer, pro-atrial natriuretic peptide (pro-ANP), brain natriuretic peptide (BNP), endothelin-1 (ET-1) and cardiac troponin I (TNI) in patients with pulmonary embolism (PE). METHODS: Patients suspected of PE had a ventilation/perfusion-single-photon emission-tomography (V/Q-SPECT), pulmonary multidetector computer tomography (MDCT) angiography, blood samples and ECG-gated cardiac CT performed the same day. RESULTS: Pro-ANP, BNP and D-dimer are associated with significantly elevated levels in PE patients with RVD. ROC curves demonstrated that D-dimer, pro-ANP and BNP were accurate for detection of RVD. CONCLUSION: Because measurements of cardiac biomarkers are inexpensive and easily obtained they may prove useful in the clinical diagnosis of RVD. However because of the small sample size, the results need to be confirmed in larger studies.