Biomedical subjects

Juergen Meyer

Publications and source records attributed to Juergen Meyer.

18 recordsLinked to original sources

PubMed2006

Magnitude and clinical relevance of translational and rotational patient setup errors: a cone-beam CT study.

PURPOSE: To establish volume imaging using an on-board cone-beam CT (CB-CT) scanner for evaluation of three-dimensional patient setup errors. METHODS AND MATERIALS: The data from 24 patients were included in this study, and the setup errors using 209 CB-CT studies and 148 electronic portal images were analyzed and compared. The effect of rotational errors alone, translational errors alone, and combined rotational and translational errors on target coverage and sparing of organs at risk was investigated. RESULTS: Translational setup errors using the CB-CT scanner and an electronic portal imaging device differed <1 mm in 70.7% and <2 mm in 93.2% of the measurements. Rotational errors >2 degrees were recorded in 3.7% of pelvic tumors, 26.4% of thoracic tumors, and 12.4% of head-and-neck tumors; the corresponding maximal rotational errors were 5 degrees , 8 degrees , and 6 degrees . No correlation between the magnitude of translational and rotational setup errors was observed. For patients with elongated target volumes and sharp dose gradients to adjacent organs at risk, both translational and rotational errors resulted in considerably decreased target coverage and highly increased doses to the organs at risk compared with the initial treatment plan. CONCLUSIONS: The CB-CT scanner has been successfully established for the evaluation of patient setup errors, and its feasibility in day-to-day clinical practice has been demonstrated. Our results have indicated that rotational errors are of clinical significance for selected patients receiving high-precision radiotherapy.

Head and Neck Neoplasms↗

PubMed2006

Adverse effect of a distended rectum in intensity-modulated radiotherapy (IMRT) treatment planning of prostate cancer.

BACKGROUND AND PURPOSE: The retrospective planning study for intensity-modulated radiotherapy (IMRT) of prostate cancer evaluated whether proximal rectum and supra-anal rectum/anal canal should be delineated as separated organs-at-risk (OARs) to achieve optimal dose distributions to the anorectal region. PATIENTS AND METHODS: For 10 patients with localized prostate cancer IMRT plans were generated with the rectum and anal canal as separated OARs (Rec-sep) and as one single OAR (Rec-tot). Two different treatment planning systems (TPS) were utilized. Influence on dose distributions to target and OARs was analyzed. RESULTS: Results from both TPS showed significantly increased doses to the distal rectum/anal canal for plans Rec-tot compared with Rec-sep in case of a distended rectum in the planning CT study: doses were increased by up to mean 31% (P = 0.02) and 18% (P = 0.03), respectively, in both TPS. For the patient with the largest rectum, the maximum dose increase was 61%. No significant differences in doses to target, bladder, femoral head and proximal rectum were seen. CONCLUSIONS: For patients with a distended rectum in the planning CT, delineation of separated OARs for proximal rectum and distal rectum/anal canal resulted in superior dose distributions to the anorectal region and therefore, we recommend this as standard procedure for IMRT planning of prostate cancer.

Algorithms↗

PubMed2006

Further evaluation of plasma sphingomyelin levels as a risk factor for coronary artery disease.

BACKGROUND: Sphingomyelin (SM) is the major phospholipid in cell membranes and in lipoproteins. In human plasma, SM is mainly found in atherogenic lipoproteins; thus, high levels of SM may promote atherogenesis. METHODS: We investigated in a median follow up of 6.0 years the association of SM with the incidence of a combined endpoint (myocardial infarction and cardiovascular death) in stable and unstable patients, and its relation to other marker of atherosclerosis in 1,102 patients with angiographically documented CAD and 444 healthy controls. RESULTS AND DISCUSSION: Logistic regression analysis showed that SM categorized by median was associated with an elevated risk for CAD (HR 3.2, 95%CI 2.5-4.0, p < 0.05). SM levels were correlated with apoB (r = 0.34) and triglyceride levels (r = 0.31). In patients with stable angina (n = 614), SM categorized by median was not related to incidence of a combined endpoint (cardiovascular death and myocardial infarction) (p = 0.844 by Log-rank test). However, in patients with acute coronary syndrome (n = 488), elevated SM was related to the combined endpoint (p < 0.05 by Log-rank test), also in a multivariate Cox regression analysis including potential confounders (HR 1.8, 95%CI 1.0-3.3, p < 0.05). CONCLUSION: The results of our study reveal that 1) human plasma SM levels are a risk factor for CAD; 2) the pro-atherogenic property of plasma SM might be related to metabolism of apoB-containing or triglyceride-rich lipoproteins; and 3) plasma SM levels are a predictor for outcome of patients with acute coronary syndrome.

Journal Article↗

PubMed2006

Influence of rectum delineation (rectal volume vs. rectal wall) on IMRT treatment planning of the prostate.

PURPOSE: To evaluate the delineation of either the rectal volume (RV) or the rectal wall (RW) in intensity-modulated radiotherapy (IMRT) for prostate cancer: influence on dose distribution to the targets and organs at risk (OARs) was investigated. MATERIAL AND METHODS: For ten patients with localized prostate cancer IMRT treatment plans were generated with the RV, wall including the filling, and the RW without the lumen as OAR (plan-RV and plan-RW), respectively. Two different IMRT treatment- planning systems (TPS) were utilized. The influence on target coverage and sparing of OARs was investigated. RESULTS: No influence was seen on target coverage and sparing of the bladder and femoral heads. Doses to the RV were significantly reduced in plan-RV for all evaluated dose levels: maximum 26% and 17%, respectively, in both TPS. The dose distribution to the RW was not significantly different between plan-RV and plan-RW. CONCLUSION: The different delineation of the OAR rectum significantly affected the inverse IMRT treatment-planning process. The use of the RV as OAR resulted in improved dose distributions to the RV. Therefore, it is suggested using the RV as OAR in IMRT treatment planning of the prostate.

Femur Head↗

PubMed2006

Cone-beam CT based image-guidance for extracranial stereotactic radiotherapy of intrapulmonary tumors.

Cone-beam CT (CB-CT) based image-guidance was evaluated for extracranial stereotactic radiotherapy of intrapulmonary tumors. A total of 21 patients (25 lesions: prim. NSCLC n = 6; pulmonary metastases n = 19) were treated with stereotactic radiotherapy (1 to 8 fractions). Prior to every fraction a CB-CT was acquired in treatment position, errors between planned and actual tumor position were measured and corrected. Intra- and inter-observer variability of manual evaluation of tumor position error was investigated and this manual method was compared with automatic image registration. Based on CB-CTs from 66 fractions the discrepancy (3-D vector) between planned and actual tumor position was 7.7 mm +/-1.3 mm. Tumor position error relative to the bony anatomy was 5.3 mm +/-1.2 mm, the correlation between bony anatomy and tumor position was poor. Intra-observer and inter-observer variability of manual evaluation of tumor position error was 0.9 mm +/-0.8 mm and 2.3 mm +/-1.1 mm, respectively. Automatic image registration showed highly reproducible results (<1 mm). However, compared with manual registration a systematic error was found in direction of predominant tumor breathing motion (2.5 mm vs 1.4 mm). Image-guidance using CB-CT was validated for high precision radiotherapy of intrapulmonary tumors. It was shown that both the planning reference and the verification image study have to consider tumor breathing motion.

Aged↗

PubMed2006

Tracking moving objects with megavoltage portal imaging: a feasibility study.

Four different algorithms were investigated with the aim to determine their suitability to track an object in conventional megavoltage portal images. The algorithms considered were the mean of the sum of squared differences (MSSD), mutual information (MI), the correlation ratio (CR), and the correlation coefficient (CC). Simulation studies were carried out with various image series containing a rigid object of interest that was moved along a predefined trajectory. For each of the series the signal-to-noise ratio (SNR) was varied to compare the performance of the algorithms under noisy conditions. For a poor SNR of -6 dB the mean tracking error was 2.4, 6.5, 39.0, and 17.2 pixels for MSSD, CC, CR and MI, respectively, with a standard deviation of 1.9, 12.9, 19.5, and 7.5 pixels, respectively. The size of a pixel was 0.5 mm. These results improved to 1.1, 1.3, 1.3, and 2.0 pixels, respectively, with a standard deviation of 0.6, 0.8, 0.8, and 2.1 pixels, respectively, when a mean filter was applied to the images prior to tracking. The implementation of MSSD into existing in-house software demonstrated that, depending on the search range, it was possible to process between 2 and 15 images/s, making this approach capable of real-time applications. In conclusion, the best geometric tracking accuracy overall was obtained with MSSD, followed by CC, CR, and MI. The simplest and best algorithm, both in terms of geometric accuracy as well as computational cost, was the MSSD algorithm and was therefore the method of choice.

Algorithms↗

PubMed2005

Prognostic value of lipoproteins and their relation to inflammatory markers among patients with coronary artery disease.

BACKGROUND: Lipoproteins and their subfractions are associated with the incidence of atherosclerotic diseases. In patients with coronary artery disease (CAD), low serum concentrations of high density lipoprotein (HDL) and high low-density lipoproteins (LDL) are correlated to myocardial infarction and cardiovascular death. There is growing evidence indicating that those lipoprotein factors are related to the inflammatory process in atherogenesis. METHODS: We investigated in a median follow up of 3.9 years the association of HDL, apolipoprotein A-I (apoA-I), LDL, apolipoprotein B (apoB), and triglycerides with the incidence of a combined endpoint (myocardial infarction and cardiovascular death) and their relation to markers of inflammation in 1298 patients with angiographically documented CAD. RESULTS: In univariate analysis, serum concentrations of apoA-I were significantly and inversely related to the combined endpoint, whereas serum concentrations of LDL, apoB, and triglycerides were not. HDL was not significantly related to the endpoint in univariate analyses (p=0.057). Multivariate analyses showed that only apoA-I is an independent predictor. ApoA-I (and HDL) was significantly related to markers of inflammation. CONCLUSION: Serum apoA-I levels were an independent predictor for fatal and non-fatal cardiovascular events in patients with CAD. This may be related to its anti-inflammatory effect.

Aged↗

PubMed2005

FDG-PET/CT imaging for preradiotherapy staging of head-and-neck squamous cell carcinoma.

PURPOSE: Image localization of head-and-neck squamous cell carcinoma lags behind current techniques to deliver a precise radiation dose with intensity-modulated radiotherapy. This pilot study prospectively examined the use of registered 18-F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT for preradiotherapy staging of the neck. METHODS AND MATERIALS: Sixty-three patients with squamous cell carcinoma of the oral cavity, oropharynx, larynx, or hypopharynx were enrolled into an institutional FDG-PET imaging protocol between September 2000 and June 2003. Of these patients, 20 went on to immediate neck dissection surgery and were studied further. Of these 20, 17 (85%) had American Joint Committee on Cancer Stage III or IV disease. All patients underwent preoperative FDG-PET and contrast-enhanced CT of the head and neck. FDG-PET/CT images were created using a nonrigid image registration algorithm developed at the University of Washington. Alternate primary and nodal gross tumor volumes were contoured with radiotherapy treatment planning software, blinded to each other and to the pathology results. One set of volumes was designed with CT guidance alone and the other with the corresponding FDG-PET/CT images. Neck dissection specimens were subdivided into surgical nodal levels intraoperatively, and the histopathologic findings were correlated with the CT and FDG-PET/CT nodal level findings. RESULTS: FDG-PET/CT detected 17 of 17 heminecks and 26 of 27 nodal zones histologically positive by dissection (100% and 96% sensitivity, respectively). The nodal level staging sensitivity and specificity for FDG-PET/CT was 96% (26 of 27) and 98.5% (68 of 69), respectively. FDG-PET/CT correctly detected nodal disease in 2 patients considered to have node-negative disease by CT alone. Agreement between the imaging results and pathology findings was stronger for FDG-PET/CT (kappa 0.95, 95% confidence interval 0.82-0.99) than for CT alone (kappa 0.81, 95% confidence interval 0.63-0.91; p = 0.06 by two-sided McNemar's testing). CONCLUSION: These early findings suggest that FDG-PET/CT is superior to CT alone for geographic localization of diseased neck node levels. Confirmatory trials to substantiate the accuracy of FDG-PET/CT neck staging should be prioritized.

Adult↗

PubMed2005

FDG-PET/CT-guided intensity modulated head and neck radiotherapy: a pilot investigation.

BACKGROUND: 2-deoxy-2[(18)F]fluoro-D-glucose-positron emission tomography (FDG-PET) imaging can be registered with CT images and can potentially improve neck staging sensitivity and specificity in patients with head and neck squamous cell cancer. The intent of this study was to examine the use of registered FDG-PET/CT imaging to guide head and neck intensity modulated radiotherapy (IMRT) planning. METHODS: Twenty patients with squamous cell carcinoma of the oral cavity, oropharynx, larynx, or hypopharynx underwent FDG-PET and contrast-enhanced CT imaging of the head and neck before neck dissection surgery. Combined FDG-PET/CT images were created by use of a nonrigid image registration algorithm. All IMRT plans were theoretical and were not used for treatment. We prescribed 66 Gy in 30 fractions to FDG-avid CT abnormalities and nodal zones directly involved with disease, without prophylactic coverage of uninvolved neck levels. Matched CT-guided IMRT plans designed according to the specifications of Radiation Therapy Oncology Group (RTOG) H-0022 were available for comparison. We investigated the feasibility of FDG-PET/CT-directed IMRT dose escalation in five patients with FDG-avid disease located away from critical normal structures. After 66 Gy, FDG-avid disease with 0.5-cm margins was boosted in 220 cGy increments until dose-limiting criteria were reached. RESULTS: Elimination of prophylactic coverage to FDG-PET/CT-negative neck levels markedly reduced mean dose (Dmean) to the contralateral parotid gland (p < .001) and Dmean to the laryngeal cartilage (p = .001). No FDG-PET/CT-directed plan missed pathologically verified nodal disease. During the dose escalation exercise, we successfully increased the dose to 95% of the planning target volume (PTV95%) to a mean of 7490 cGy (range, 7153-8098 cGy). CONCLUSIONS: We demonstrate early proof of the principle that FDG-PET/CT-guided IMRT planning can selectively target and intensify treatment of head and neck disease while reducing critical normal tissue doses. Routine clinical use of such planning should not be engaged until the accuracy of FDG-PET/CT is fully validated. Future directions, including refinement of treatment to gross disease and radiologically uninvolved neck nodal levels, are discussed.

Adult↗

PubMed2005

Herpesvirus DNA (Epstein-Barr virus, herpes simplex virus, cytomegalovirus) in circulating monocytes of patients with coronary artery disease.

BACKGROUND: The underlying mechanism of the chronic inflammatory process in atherosclerosis is still unknown. As a possible trigger, several studies in recent years have suggested that different viruses and bacteria are associated with atherosclerotic diseases. METHODS: We applied polymerase chain reaction to analyse whether Epstein-Barr virus (EBV), herpes simplex virus (HSV), and cytomegalovirus (CMV) DNA could be detected in CD14 + cells from 184 patients with angiographically documented coronary artery disease (CAD) (74 patients with stable angina (SAP), 51 patients with unstable angina (UAP), and 59 patients with myocardial infarction (MI)) and from 52 healthy controls. RESULTS: In two patients (one patient with SAP, one patient with UAP) with CAD and one healthy control, DNA from CMV was found (p = 0.469). HSV DNA was detected in one patient (SAP) but not in any controls (p = 0.644). EBV DNA was found in nine patients (three patients with SAP, one patient with UAP, five patients with MI), and two controls (p = 0.752). CONCLUSION: Our data do not support the hypothesis that herpesvirus-infected monocytes are related to the incidence of human coronary atherosclerosis.

Age Factors↗

PubMed2004

Serum sphingomyelin levels are related to the clearance of postprandial remnant-like particles.

It is known that sphingomyelin (SM) content is higher in apolipoprotein B-containing particles (BLps) than in high density lipoproteins and that BLp levels, including chylomicrons and their remnant particles, are positively related to atherosclerosis. To evaluate the relationship between serum SM and postprandial remnant particle levels, we determined SM, triglyceride (TG), and cholesterol levels in serum and in remnant-like particles (RLPs) before and 3, 5, 7, and 10 h after a high-fat meal in 31 healthy subjects. We found that serum SM, like serum TG, was increased to its maximum 3 h after fat loading and then gradually decreased to basal levels after 10 h. More important, we determined that SM and TG levels in RLPs were parallel. Serum SM was positively correlated with serum TG (P <0.001), RLP SM (P <0.001), RLP TG (P <0.001), and RLP cholesterol (P <0.001) levels. It is our conclusion that serum SM is a marker for the clearance of RLPs.

Apolipoproteins B↗

PubMed2004

Influence of contrast agent dose and image acquisition timing on the quantitative determination of nonviable myocardial tissue using delayed contrast-enhanced magnetic resonance imaging.

BACKGROUND: Delayed contrast-enhanced magnetic resonance imaging (ceMRI) has been shown to identify areas of irreversible myocardial injury due to infarction (MI) with high spatial resolution, allowing precise quantification of nonviable (hyperenhanced) myocardium. The aim of our study was to investigate the size of nonviable myocardium quantitatively as a function of time post-contrast when inversion time is held constant in patients post-myocardial infarction using two contrast agent (CA) doses. METHODS: Nine patients with chronic MI underwent two MR scans on a 1.5 Tesla system. Contrast-enhanced MRI data in two short-axis (SA) slices were continuously acquired until 40 minutes after CA injection [gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), 0.1 mmol/kg body weight = single dose] interrupted only for a complete stack of SA slices encompassing the entire left ventricle (LV) between minutes 20 and 28. Left ventricular mass showing hyperenhancement was determined. The measurement was repeated on the subsequent day with double dose CA (0.2 mmol/kg body weight). Differences of signal intensities for hyperenhanced, nonhyperenhanced myocardium, and LV cavity were calculated. RESULTS: Total mass of hyperenhancement from a complete SA stack acquired between minutes 20 and 28 was lower for single dose CA [9.0% vs. 14.2% for single and double dose, respectively (p = 0.03)]. Ten to 18 minutes after CA injection, there was no significant difference between the two doses and to an internal reference for both single and double dose. For single dose the image contrast between hyperenhancement and LV cavity was superior (minutes 10 to 16, p < 0.05) but inferior between hyperenhanced and nonhyperenhanced myocardium (minutes 6 to 16, p < 0.05). CONCLUSION: Myocardial infarct size measurements are a function of time postcontrast when inversion time is held constant regardless of the contrast agent dose. These data underscore the fact that a standardized imaging protocol that defines how the appropriate inversion time should be selected is needed for comparison of results obtained at various cMR sites.

Contrast Media↗

PubMed2004

CD14+CD16+ monocytes in coronary artery disease and their relationship to serum TNF-alpha levels.

Monocytes play a central role in the inflammatory disease atherosclerosis. CD14+CD16+ monocytes are considered proinflammatory monocytes, as they have an increased capacity to produce proinflammatory cytokines, such as TNF-alpha, and are elevated in various inflammatory diseases. We hypothesized that patients with coronary artery disease (CAD) have increased levels of CD14+CD16+ monocytes, and that CD14+CD16+ monocytes are associated with inflammation markers. We investigated CD14+CD16+ monocytes in 247 patients with CAD and 61 control subjects using flow cytometry. In addition serum concentrations of TNF-alpha, IL-6, and Hs-CRP were assessed. Patients with CAD had higher levels of CD14+CD16+ monocytes than controls (13.6% versus 11.4%; p<0.001). Logistic regression analysis including quartiles of CD14+CD16+ monocytes showed that CD14+CD16+ monocytes were associated with prevalence of CAD (OR 4.9, 95% CI 2.5-19.1, for subjects in the fourth quartile in comparison to subjects in the first quartile). The association between CD14+CD16+ monocytes and CAD remained independently significant after adjustment for most potential confounders (OR 5.0, 95% CI 1.2-20.0). Serum concentrations of TNF-alpha were elevated in subjects within the highest quartiles of CD14+CD16+ monocytes (p=0.018). Our study showed that increased numbers of CD14+CD16+ monocytes are associated with coronary atherosclerosis and TNF-alpha. In accordance, recent animal studies suggest a possibly important role of these monocytes in the development of atherosclerosis.

Aged↗

PubMed2003

High plasma phospholipid transfer protein levels as a risk factor for coronary artery disease.

OBJECTIVE: Plasma phospholipid transfer protein (PLTP) mediates both net transfer and exchange of phospholipids between different lipoproteins. Animal studies have shown that it is closely related to the development of atherosclerosis. PLTP-deficient mice have demonstrated increased antioxidation potential as well as a decrease in apolipoprotein B secretion and atherosclerotic lesions. In humans, high PLTP is associated with type II diabetes and obesity. METHODS AND RESULTS: To assess the relationship between PLTP activity and coronary artery disease (CAD), a novel, high-throughput method to measure plasma PLTP activity was used, relating it to CAD in 1102 cases and 444 controls. This demonstrated that PLTP activity in patients with CAD was significantly higher than in controls (25.5 versus 22.4 pmol/microL per h; P<0.0001). Using multivariate logistic regression analysis, PLTP activity was found to have independent predictive value for CAD. Patients within the highest quintile of PLTP activity revealed a 1.9-fold increase in risk for CAD compared with patients within the lowest quintile. CONCLUSIONS: These findings indicate that PLTP activity is positively and independently related to CAD and suggest that (1) prospective studies to evaluate this relationship are warranted and (2) PLTP should be considered a therapeutic target.

Adult↗

PubMed2003

Diagnostic value of routine clinical parameters in acute myocardial infarction: a comparison to delayed contrast enhanced magnetic resonance imaging. Delayed enhancement and routine clinical parameters after myocardial infarction.

AIMS: Contrast enhanced magnetic resonance imaging (ceMRI) has been shown to reliably identify irreversible myocardial injury. The aim of this study was to compare the findings on ceMRI with routine clinical markers of myocardial injury in patients with acute myocardial infarction (MI). METHODS AND RESULTS: Twenty-four patients with acute MI were investigated at 1.5 T. The global myocardial function was analysed with a standard cine MR protocol and a stack of short axis slices encompassing the entire left ventricle. Corresponding short axis slices were acquired for delayed ceMRI 15-20 min after the administration of 0.2 mmol gadolinium-DTPA/kg body weight. Mass of hyperenhancement and peak creatine kinase release (peak CK) was determined for each patient. The presenting 12-lead ECG was analysed for ST-elevation on admission and later development of Q-waves. Mass of hyperenhancement correlated moderately well to peak CK (r = 0.65, p < 0.01) and endsystolic volume index (r = 0.55, p < 0.01). Mass of hyperenhancement was inversely correlated to ejection fraction (r = -0.50, p = 0.02). Neither the presence of ST elevation on the admission ECG nor the later development of Q-waves did relate to the transmural extent of hyperenhancement and to the mass of hyperenhancement. CONCLUSION: Mass of hyperenhancement significantly correlates to global myocardial function and to peak CK. However, there is no relationship between the findings in ceMRI and 12-lead ECG abnormalities on admission suggesting an advantage of ceMRI in defining transmural extent and depicting small areas of necrosis.

Adult↗

PubMed2003

Fondaparinux and enoxaparin in comparison to unfractionated heparin in preventing thrombus formation on mechanical heart valves in an ex vivo rabbit model.

The aim of the present study was to investigate the efficacy of three different parenterally administered anticoagulants for the prevention of thrombus formation on artificial heart valves in an experimental rabbit model. Unfractionated heparin was administered intravenously in group I (n = 10), Enoxaparin subcutaneously in group II (n = 10), fondaparinux intravenously in group III (n = 10), and no medication was administered to group IV (n = 9). Leaflets from Sulzer Carbomedics bileaflet mechanical heart valves were placed in a flow chamber. The flow chamber was filled with blood in a continuous circulation between the carotid artery and the jugular vein. In group IV the flow chamber was clotted after a median of 15 minutes of circulation. Weight analysis before and after 1 h of perfusion showed that the median thrombus weight was 18.0 mg in group I, 17.7 mg in group II, 20.3 mg in group III, and 30.8 mg in group IV. Further analysis by electron microscopy showed similar results regarding deposition of fibrin, platelets, and erythrocytes on leaflet surfaces. Fondaparinux and subcutaneously administered enoxaparin were as effective as intravenously administered unfractionated heparin in preventing thrombus formation on artificial heart valve leaflets in our investigation. This rabbit model, in which the heart valve leaflets were exposed to rabbit blood for a short time under laminar flow, should be further evaluated with respect to whether it can provide information about anti-thrombotic regimens in patients after mechanical heart valve replacement.

Animals↗

PubMed2002

Assessment of cardiac performance using Tei indices in patients undergoing pulmonary thromboendarterectomy.

BACKGROUND: This study was designed to evaluate left and right ventricular performance using Tei indices in patients with severe chronic thromboembolic pulmonary hypertension undergoing pulmonary thromboendarterectomy (PTE). The Doppler-derived indices are easily measurable indicators of ventricular function based on nongeometric assessment, which helps overcome some of the difficulties entailed in the geometric assessment of left ventricular (LV) and right ventricular (RV) function in pulmonary hypertension. METHODS: The indices were derived for 24 patients (aged 54+/-14 years) before and after PTE. Calculation of these indices was based on the duration of two time intervals using the formula (A - B)/B, where A is the interval between cessation and onset of mitral inflow (or tricuspid inflow) and B is LV or RV ejection time. In addition, LV and RV end-diastolic and end-systolic chamber areas were determined using two-dimensional echocardiography, and systolic function was calculated. Mean pulmonary artery pressure was determined invasively. RESULTS: PTE led to a significant reduction of mean pulmonary artery pressure (46+/-10 versus 25+/-6 mm Hg; p < 0.05). LV and RV indices were abnormally high before surgery, declined significantly afterwards, and then almost matched normal values (0.61+/-0.26 versus 0.37+/-0.18; p < 0.05 and 0.55+/-0.22 versus 0.37+/-0.13; p < 0.05). Geometric assessment of the left and right ventricle also showed impaired systolic function before PTE, with significant improvement after surgery. CONCLUSIONS: LV and RV Tei indices allow a quantitative assessment of ventricular function in patients undergoing PTE. Lower indices after surgery reflect an improvement of the previously impaired cardiac function. Our results emphasize the value of PTE in the treatment of chronic thromboembolic pulmonary hypertension.

Adult↗

PubMed2002

Improvement of tricuspid regurgitation after pulmonary thromboendarterectomy.

BACKGROUND: For patients with chronic thromboembolic pulmonary hypertension who undergo pulmonary thromboendarterectomy (PTE) it has not yet been systematically investigated how operation affects the severity of tricuspid regurgitation (TR). This study sought (1) to evaluate the extent of TR reversibility after operation, (2) to identify potential predictors of the reversibility of TR, and (3) to investigate the influence of geometric and hemodynamic alterations on the extent of TR severity. METHODS: Thirty-nine patients (55+/-12 years) undergoing PTE without tricuspid valve repair were investigated before and 13+/-8 days after operation by Doppler color flow mapping. Geometry of the tricuspid valve as well as right ventricular size and function were determined with echocardiography. Mean pulmonary arterial pressure was determined invasively. RESULTS: After PTE, mean pulmonary arterial pressure was significantly lower (48+/-10 versus 25+/-7 mm Hg, p < 0.05). Most of the patients had a distinct reduction of TR, and the improvement trend showed on the severity scale: number of patients with 4+TR (23 --> 4), 3+TR (12 --> 12), 2+TR (2 --> 13), and 1+TR (2 --> 10). Examination after PTE revealed profound reduction of right ventricular size and annulus diameter, with a normalization of the valvular geometry. However, none of the study variables were useful as indicators of the postoperative outcome. CONCLUSIONS: After PTE without additional valve repair most patients show significantly reduced severity of TR soon afterward; the very few cases in which TR does not improve remain unidentifiable before operation. Our recommendation is consequently to refrain from additional tricuspid repair in patients undergoing PTE.

Adult↗