Renale Denervation

Methodical Innovation

Renal denervation is a catheter-based, endovascular procedure for the treatment of drug-resistant hypertension. The aim of the therapy is to lower the blood pressure <?140/90 mmHg.

Performance

Even after successful minimally invasive therapy patients usually continue to take three or more antihypertensive drugs. Currently there is no evidence that renal denervation is a good option for the treatment of well-controlled hypertension in order to dispense with antihypertensive drugs. In carefully selected patients the mean reduction in systolic and diastolic blood pressure after renal denervation is 25–30 mmHg and 10–15 mmHg, respectively.

Achievements

Procedure-related or device-related complications are rare. Ablation catheters from different manufactures differ greatly in handling properties; however, up to now there is no evidence for relevant differences in safety and efficacy between the devices available.     

First-in-Man Experience with a Novel Catheter-Based Renal Denervation System of Ultrasonic Ablation in Patients with Resistant Hypertension

Purpose

To report results of renal denervation (RDN) with the first catheter-based, non–balloon occlusion ultrasonic system in patients with resistant hypertension.

Renal Sympathetic Denervation by CT-Guided Ethanol Injection: A Phase II Pilot Trial of a Novel Technique

Objectives

CT-guided ethanol-mediated renal sympathetic denervation in treatment of therapy-resistant hypertension was performed to assess patient safety and collect preliminary data on treatment efficacy.

Materials and Methods

Eleven patients with therapy-resistant hypertension (blood pressure of >160 mmHg despite three different antihypertensive drugs including a diuretic) and following screening for secondary causes were enrolled in a phase II single arm open label pilot trial of CT-guided neurolysis of sympathetic renal innervation. Primary endpoint was safety, and secondary endpoint was a decrease of the mean office as well as 24-h systolic blood pressure in follow-up. Follow-up visits at 4 weeks, 3, and 6 months included 24-h blood pressure assessments, office blood pressure, laboratory values, as well as full clinical and quality of life assessments.

Results

No toxicities ≥3° occurred. Three patients exhibited worsened kidney function in follow-up analyses. When accounting all patients, office systolic blood pressure decreased significantly at all follow-up visits (maximal mean decrease ?41.2 mmHg at 3 months). The mean 24-h systolic blood pressure values decreased significantly at 3 months, but not at 6 months (mean: ?9.7 and ?6.3 mmHg, respectively). Exclusion of five patients who had failed catheter-based endovascular denervation and/or were incompliant for antihypertensive drug intake revealed a more pronounced decrease of 24-h systolic blood pressure (mean: ?18.3 and ?15.2 mmHg at 3 and 6 months, p = 0.03 and 0.06).

Conclusion

CT-guided sympathetic denervation proved to be safe and applicable under various anatomical conditions with more renal arteries and such of small diameter.

     

Incidence and Cause of Hypertension During Adrenal Radiofrequency Ablation

Purpose

To evaluate the incidence and cause of hypertension prospectively during adrenal radiofrequency ablation (RFA).

Methods

For this study, approved by our institutional review board, written informed consent was obtained from all patients. Patients who received RFA for adrenal tumors (adrenal ablation) and other abdominal tumors (nonadrenal ablation) were included in this prospective study. Blood pressure was monitored during RFA. Serum adrenal hormone levels including epinephrine, norepinephrine, dopamine, and cortisol levels were measured before and during RFA. The respective incidences of procedural hypertension (systolic blood pressure >200?mmHg) of the two patient groups were compared. Factors correlating with procedural systolic blood pressure were evaluated by regression analysis.

Results

Nine patients underwent adrenal RFA and another 9 patients liver (n?=?5) and renal (n?=?4) RFA. Asymptomatic procedural hypertension that returned to the baseline by injecting calcium blocker was found in 7 (38.9%) of 18 patients. The incidence of procedural hypertension was significantly higher in the adrenal ablation group (66.7%, 6/9) than in the nonadrenal ablation group (11.1%, 1/9, P?<?0.0498). Procedural systolic blood pressure was significantly correlated with serum epinephrine (R ²?=?0.68, P?<?0.0001) and norepinephrine (R ²?=?0.72, P?<?0.0001) levels during RFA. The other adrenal hormones did not show correlation with procedural systolic blood pressure.

Conclusion

Hypertension occurs frequently during adrenal RFA because of the release of catecholamine.     

Does Renal Artery Supply Indicate Treatment Success of Renal Denervation?

Purpose

Renal denervation (RDN) emerged as an innovative interventional antihypertensive therapy. With the exception of pretreatment blood pressure (BP) level, no other clear predictor for treatment efficacy is yet known. We analyzed whether the presence of multiple renal arteries has an impact on BP reduction after RDN.

Methods

Fifty-three patients with treatment-resistant hypertension (office BP ≥ 140/90 mmHg and 24-h ambulatory BP monitoring (≥130/80 mmHg) underwent bilateral catheter-based RDN. Patients were stratified into one-vessel (OV) (both sides) and at least multivessel (MV) supply at one side. Both groups were treated on one vessel at each side; in case of multiple arteries, only the dominant artery was treated on each side.

Results

Baseline clinical characteristics (including BP, age, and estimated glomerular filtration rate) did not differ between patients with OV (n = 32) and MV (n = 21). Office BP was significantly reduced in both groups at 3 months (systolic: OV ?15 ± 23 vs. MV ?16 ± 20 mmHg; diastolic: OV ?10 ± 12 vs. MV ?8 ± 11 mmHg, both p = NS) as well as 6 months (systolic: OV ?18 ± 18 vs. MV ?17 ± 22 mmHg; diastolic: OV ?10 ± 10 vs. ?10 ± 12 mmHg, both p = NS) after RDN. There was no difference in responder rate (rate of patients with office systolic BP reduction of at least 10 mmHg after 6 months) between the groups.

Conclusion

In patients with multiple renal arteries, RDN of one renal artery—namely, the dominant one—is sufficient to induce BP reduction in treatment-resistant hypertension.     

Potential of right to left ventricular volume ratio measured on chest CT for the prediction of pulmonary hypertension: correlation with pulmonary arterial systolic pressure estimated by echocardiography

Objectives

To investigate the correlation of right ventricular (RV) to left ventricular (LV) volume ratio measured by chest CT with pulmonary arterial systolic pressure (PASP) estimated by echocardiography.

Methods

104 patients (72.47?±?13.64?years; 39 male) who had undergone chest CT and echocardiography were divided into two groups (hypertensive and normotensive) based upon an echocardiography-derived PASP of 25?mmHg. RV to LV volume ratios (RV_V/LV_V) were calculated. RV_V/LV_V was then correlated with PASP using regression analysis. The Area Under the Curve (AUC) for predicting pulmonary hypertension on chest CT was calculated.

Results

In the hypertensive group, the mean PASP was 46.29?±?14.42?mmHg (29-98?mmHg) and there was strong correlation between the RV_V/LV_V and PASP (R?=?0.82, p?V/LV_V were 0.990 and 0.892. RV_V/LV_V was 1.01?±?0.44 (0.51-2.77) in the hypertensive and 0.72?±?0.14 (0.52-1.11) in the normotensive group (P <0.05). With 0.9 as the cutoff for RV_V/LV_V, sensitivity and specificity for predicting pulmonary hypertension over 40?mmHg were 79.5?% and 90?%, respectively. The AUC for predicting pulmonary hypertension was 0.87

Conclusion

RV/LV volume ratios on chest CT correlate well with PASP estimated by echocardiography and can be used to predict pulmonary hypertension over 40?mmHg with high sensitivity and specificity.

Key Points

? Chest CT is widely used in patients who may have pulmonary hypertension. ? Cardiac ventricular volume ratios on chest CT correlate with pulmonary arterial systolic pressure. ? A R/L ventricular volume ratio >0.9 usually indicates pulmonary hypertension >40?mmHg. ? Information available on routine chest CT may help predict pulmonary hypertension.     

New guidelines on the use of iodinated contrast media: a report on an implementation project

Purpose

The aim of this paper is to report on the implementation of new guidelines on the use of injectable iodinated contrast media (ICM) at our workplace and specific protocols for the preparation of patients at risk.

Materials and methods

Operators received training with continuing medical education (CME) credits. The new documentation (patient history/screening form and informed consent form) is available on the hospital Web site and requests serum creatinine determination with estimation of glomerular filtration rate (GFR) for every patient. Additional tests are required for high-risk patients only.

Results

Attendance rates were 57.2% among referring physicians and 74.5% among Radiology Department personnel. The Cockcroft-Gault formula was used to estimate GFR in adults. The main problem encountered in the implementation process was that referring physicians failed to evaluate the GFR in 80% of patients, with low GFR being discovered in the Radiology Department on the day of examination in 20% of patients, resulting in a need to reschedule the examination.

Conclusions

Although not an easy task, implementation of the new guidelines for ICM use is both feasible and necessary. An additional refresher training course for personnel and GFR evaluation of the patient on referral are indispensable to ensure proper preparation of patients at increased risk of adverse reactions to ICM.     

Effects of atrial natriuretic peptide on glomerular filtration rate in essential hypertension: a radionuclide study

A number of studies show that atrial natriuretic peptide (ANP) raises renal sodium excretion with a concomitant increase in glomerular filtration rate (GFR) in both experimental animals and normal humans. Studies using indirect evaluation of GFR have provided less consistent results in hypertensive patients. We studied the effects of intravenously administered (iv) -human ANP on GFR in patients with hypertension by a radionuclide technique using technetium 99m diethylenetriaminepenta-acetic acid. In six patients (ANP group), GFR was determined under control conditions, during iv ANP (initial bolus of 0.5 g/kg followed by a 21-min maintenance infusion at 0.05 g · kg^–1 · min^–1) and during a recovery phase. In six other patients (control group), GFR was determined under control conditions, during saline iv infusion and during recovery. The two groups did not differ with respect to age, sex, basal blood pressure, heart rate or GFR. In the ANP group, the infusion of the peptide induced a significant decrease of mean blood pressure (from 133 ± 5 to 120 ± 5 mmHg, P < 0.01), no change in heart rate and a significant increase in GFR (from 104 ± 4 to 125 ± 5 ml/min, P < 0.01). During recovery, blood pressure, heart rate and GFR were not different from the values recorded under control conditions. No changes in blood pressure, heart rate or GFR (from 106 ± 5 to 108 ± 5 ml/min, n.s.) were detected during saline infusion in the control group. Our results demonstrated that in patients with essential hypertension, ANP induces an augmentation in GFR in spite of a decrease in blood pressure; this suggests a unique role for atrial peptide-related drugs in the treatment of human hypertension.     

A risk–benefit analysis of alternating low-pressure CO2 insufflation and fluid medium in arthroscopic knee ACL reconstruction

Purpose

The purpose of this study was to test the hypothesis that the surgical technique using alternating fluid irrigation and carbon dioxide (CO₂) gas medium as a means of knee joint distension during arthroscopy is a safe and effective method, compared to traditional fluid arthroscopy.

Methods

This prospective randomized comparative study involved 94 patients undergoing the same arthroscopic ACL reconstruction surgical procedure except for the medium used to distend the joint: In a first group of 48 patients (“ACL gas” group), CO₂ insufflation was mainly used, at a low pressure of 40–50 mmHg, alternating with a fluid medium for knee joint washout only. In the second group of 46 patients, classical arthroscopic joint distension by fluid was used, with a pump pressure of 50–70 mmHg. Early pre- and post-operative complications, duration of surgery, intraoperative monitoring data and particularly the end-tidal carbon dioxide (EtCO₂) as a marker of CO₂ blood diffusion were prospectively collected.

Results

EtCO₂ and other monitoring data changes before and after tourniquet release were not different between the two groups. Tourniquet time was significantly longer when using fluid rather than gas. We observed 3 cases of small and localized subcutaneous emphysema, resolving completely within hours. Hematoma and reflex sympathetic dystrophy occurred more often in the “ACL fluid” group, with no statistical significance.

Conclusion

Low-pressure CO₂ knee joint insufflation proved to be a safe technique capable of improving surgical comfort compared with the use of fluid alone. The CO₂ blood diffusion measured by end-tidal carbon dioxide monitoring during ACL arthroscopic reconstruction was similar with or without gas insufflation.

Level of evidence

Randomized controlled trial, Level I.     

Angioplasty for pediatric renovascular hypertension: a 13-year experience

PURPOSE

We aimed to evaluate the long-term outcome and efficacy of percutaneous transluminal renal angioplasty (PTRA) for pediatric renal artery stenosis (RAS), which is an important cause of medication-refractory pediatric hypertension.

MATERIALS AND METHODS

We retrospectively evaluated 22 hypertensive children (age range, 3–17 years) who underwent PTRA from February 2000 to July 2012. Sixteen patients had Takayasu arteritis and six fibromuscular dysplasia. Five were not included in the statistical analysis due to loss to follow-up.

RESULTS

Technical success was achieved in 32 of 34 procedures (94.1%). The stenosis rate decreased from 84.5% before PTRA to 20.1% after PTRA. Treatment was effective in 72.7% (16/22) of patients, including complete cure in 27.3% (6/22) and improvement in 45.5% (10/22). Systolic and diastolic blood pressures decreased from 153±19.1 to 131.7±21.4 mmHg and from 97.9±14.2 to 83.6±19.3 mmHg, respectively (P < 0.01). Number of antihypertensive agents decreased from 2.7 to 0.5 per patient. Restenosis was detected in 40.9% (9/22) of patients, with a restenotic interval of 11.8 months (range, 3–47 months). Lesion length was strongly correlated with clinical success (cure and improvement) (independent-sample t test, P < 0.001; binary logistic regression, P = 0.040).

CONCLUSION

Lesion length is an important determination of clinical success with PTRA for pediatric RAS. PTRA is an appropriate treatment option for pediatric renovascular hypertension due to Takayasu arteritis and fibromuscular dysplasia.Although hypertension affects only 1%–2% of children and adolescents based on reliable assessments (1, 2), it is a major risk factor for cerebrovascular disease, myocardial infarction, and renal failure. Renal artery stenosis (RAS), a vascular disease, leads to 5%–25% of pediatric hypertension. Although a few conditions, including Kawasaki disease, polyarteritis nodosa, Wegener’s granulomatosis, neurofibromatosis, Williams syndrome, and midaortic syndrome, may cause RAS in pediatric patients (3, 4), Takayasu arteritis (TA) is the most common cause of pediatric RAS in the East, especially in China, Korea, and India (5, 6). Fibromuscular dysplasia (FMD) is another important cause of RAS in children, particularly in Western countries. A substantial proportion of patients with RAS suffer from hypertension and poor sequelae. Additionally, pediatric hypertension is strongly associated with hypertension in adults (7). However, blood pressure is not frequently measured in children. Due to the lack of sufficient information on blood pressure, renovascular hypertension is often ignored and/or diagnosed with a considerable time delay by referring physicians (5). Despite many antihypertensive agents, valid control of blood pressure is often impossible. Moreover, normalized blood pressure with multiple drugs may result in underperfusion of the kidney and cerebral blood vessels, thereby aggravating multiple organ dysfunction. Therefore, surgical interventions are considered as an alternative strategy to achieve an adequate control of blood pressure in pediatric patients (8).Here, we present 13 years of data on the outcomes of 22 children with renovascular hypertension caused by TA or FMD following treatment with a percutaneous transluminal renal angioplasty (PTRA) procedure.     

Nichtinvasive Bestimmung des intrakraniellen Drucks

Clinical/methodical issue

The intracranial pressure (ICP) is a crucially important parameter for diagnostic and therapeutic decision-making in patients with hydrocephalus.

Standard radiological methods

So far there is no standard method to non-invasively assess the ICP. Various approaches to obtain the ICP semi-invasively or non-invasively are discussed and the clinical application of a magnetic resonance imaging (MRI)-based method to estimate ICP (MR-ICP) is demonstrated in a group of pediatric patients with hydrocephalus.

Methodical innovations

Arterial inflow, venous drainage and craniospinal cerebrospinal fluid (CSF) flow were quantified using phase-contrast imaging to derive the MR-ICP.

Performance

A total of 15?patients with hydrocephalus (n=9 treated with shunt placement or ventriculostomy) underwent MRI on a 3?T scanner applying retrospectively-gated cine phase contrast sequences. Of the patients six had clinical symptoms indicating increased ICP (age 2.5–14.61?years, mean 7.4?years) and nine patients had no clinical signs of elevated ICP (age 2.1–15.9?years; mean 9.8?years; all treated with shunt or ventriculostomy). Median MR-ICP in symptomatic patients was 24.5?mmHg (25th percentile 20.4?mmHg; 75th percentile 44.6?mmHg). Median MR-ICP in patients without acute signs of increased ICP was 9.8?mmHg (25th percentile 8.6?mmHg; 75th percentile 11.4?mmHg). Group differences were significant (p <?0.001; Mann-Whitney U-test).

Achievements

The MR-ICP technique is a promising non-invasive tool for estimating ICP.

Practical recommendations

Further studies in larger patient cohorts are warranted to investigate its application in children with hydrocephalus.     

Endovascular treatment of transplanted renal artery stenosis with PTA/stenting

Purpose

We evaluated the effectiveness of endovascular treatment with percutaneous transluminal balloon angioplasty (PTA)/stenting of transplanted renal artery stenosis (TRAS).

Materials and methods

Between January 2005 and December 2010, 17 patients (4 women, 13 men; mean age 60.9 years) with TRAS underwent PTA/stenting. The parameters analysed were: technical success, pre- and post-treatment serum creatinine (SCr) and blood pressure (BP), average number of antihypertensive drugs administered before and after treatment and vessel patency on colour Doppler ultrasound (CDUS) at 1, 3, 6 and 12 months and once a year thereafter.

Results

Technical success was 100%. During a mean follow-up of 28.3±18.7 months, there was a statistically significant reduction in SCr and BP values. In 18 % of cases, moderate (<60%) restenosis was observed on CDUS without renal failure and not requiring new treatment. There was a reduction in antihypertensive drugs from an average of 3.5±0.5 to 1.5±0.5.

Conclusions

Consistent with the literature data, our experience shows that endovascular treatment with PTA/stenting is a safe and effective option for managing TRAS and can thus be considered the method of choice.     

Diffusional kurtosis imaging analysis in patients with hypertension

Purpose

Hypertension is associated with substantial morbidity in Japan. The aim of this work was to evaluate whether hypertension is associated with white matter microstructural changes by using diffusional kurtosis imaging (DKI).

Methods

We explored the regional patterns of white matter alteration in 15 hypertensive middle-aged male participants and 11 normotensive controls by using DKI-based whole-brain analysis. In addition, we investigated whether the observed white matter microstructural changes were related to systolic or diastolic blood pressure by using Pearson’s correlation coefficient analysis.

Results

Mean diffusional kurtosis (MDK) values were significantly higher in hypertensive participants than in normotensive participants (P < 0.05; family-wise error correction for multiple comparisons), indicating widespread microstructural changes in white matter. Moreover, we noted a statistically significant positive correlation between systolic and diastolic blood pressure and MDK values of the whole brain.

Conclusion

Our study suggests that microstructural white matter changes occur in middle-aged men with hypertension, even before the onset of cerebrovascular disease. Thus, DKI might be used as a screening tool for risk of cerebrovascular disease. This highlights the need to further elucidate the relationship between hypertension and DKI of the brain.     

Monitoring renal function during chemotherapy

Purpose

Renal function is monitored during chemotherapy because chemotherapeutic drugs are excreted by the kidneys and are potentially nephrotoxic. Doses are adjusted according to the glomerular filtration rate (GFR), i.e. the more reduced the GFR, the lower the treatment dose. Plasma clearance of ⁵¹Cr-EDTA is a reliable indicator of GFR before and during treatment with potentially nephrotoxic drugs, but its measurement is costly. GFR can also be estimated using an algorithm that converts plasma creatinine concentration to GFR, e.g. the MDRD equation. The aim of this investigation was to evaluate the reliability of estimated GFR (eGFR) in detecting changes in GFR as assessed by the MDRD equation in cancer patients treated with nephrotoxic chemotherapeutic drugs.

Methods

We included all patients from the Department of Oncology undergoing chemotherapy who were referred to the Department of Nuclear Medicine for measurement of GFR by the ⁵¹Cr-EDTA plasma clearance technique at least four times during the study period of 12?months. The eGFR was calculated from plasma creatinine concentration and the MDRD formula. GFR was determined by the ⁵¹Cr-EDTA plasma clearance method.

Results

In 48 patients with a mean age of 47?years, GFR decreased from 86 to 73?ml/min/1.73?m² (mean values, p?Conclusion Neither creatinine plasma concentration nor eGFR (MDRD) can be recommended as a replacement for measurement of GFR with the ⁵¹Cr-EDTA plasma clearance method in patients treated with nephrotoxic cytostatic drugs.     

Nitric oxide and blood pressure responses to short-term resistance training in adults with and without type-2 diabetes: a randomized controlled trial

Background

Type-2 diabetes (T2D) is associated with endothelial dysfunction, increase in sympathetic tone and several cardiovascular disorders, such as systemic arterial hypertension and coronary artery disease.

Aims

To determine the effects of resistance training (RT) on the responses of nitric oxide (NO) and blood pressure (BP) in individuals with T2D and their controls peers.

Methods

Randomized controlled trial in which T2D patients and non-diabetic individuals (ND) performed 8 weeks of RT. Participants were 22 women and 12 men (age 62.3?±?2.5 years) that were randomly allocated into four groups: T2D training (n?=?9), ND training (n?=?10), T2D control (n?=?8), and ND control (n?=?7). NO and BP were measured before and after the whole intervention.

Results

There were no significant differences in nitrite concentrations between and within groups, with values varying between 1.22?±?0.15 and 1.45?±?0.13 Log µM. The T2D and ND experimental groups decreased systolic blood pressure (SBP) by 8.1 and 1.4 mmHg, respectively. However, the control groups showed elevation of SBP (3.6 mmHg for T2D and 4.1 mmHg for ND). Although none of these changes were significant (p?>?0.05). In addition, T2D subjects who did not undergo the training increased diastolic blood pressure (p?=?0.030) and mean arterial pressure (p?=?0.054).

Conclusions

Eight weeks of RT does not increase NO bioavailability, and in turn, does not reduce BP in T2D patients—though it prevented its increase.

Trial registration

ensaiosclinicos.gov.br (ID: RBR-4d39z9).

     

ECG-gated computed tomography to assess pulmonary capillary wedge pressure in pulmonary hypertension

Objective

We propose a non-invasive method for diagnosing post-capillary pulmonary hypertension (PH group 2). We evaluated pulmonary capillary wedge pressure (PCWP) by studying the left atrium (LA) on thoracic ECG-gated CT compared with right heart catheterisation (RHC).

Methods

We retrospectively studied 54 patients with suspected PH or followed for PH who underwent thoracic ECG-gated CT and RHC within 15 days. The diagnostic accuracy of CT morphological and functional data of the LA for the detection of PCWP >15 mmHg, evaluated by two independent readers, was assessed using correlation and receiver-operating characteristic (ROC) analysis.

Results

Interobserver agreement was high (r?=?0.97–0.99). Correlations were found between PCWP and the morphological criteria of the LA such as anteroposterior diameter at 0 % of the R-R interval (r?=?0.70, P?≤?0.001) as well as at 40 % (r?=?0.69, P?≤?0.001). ROC curves constructed with a threshold value of PCWP?>?15 mmHg showed an area under the curve between 0.88 and 0.91. Significant correlations were found between PCWP and functional criteria of the LA, including distensibility (r?=??0.49, P?≤?0.001) and ejection fraction (r?=??0.58, P?≤?0.001).

Conclusion

Thoracic ECG-gated CT in a PH workup helps distinguish between pre- and post-capillary PH.

Key Points

? Computed tomography may help differentiate the various types of pulmonary hypertension (PH). ? Post-capillary PH group 2 is due to left heart disease. ? Right heart catheterisation is used to separate pre- and post-capillary PH. ? Left atrium anteroposterior diameter measured on CT is of value. ? ECG-gated CT helps clinicians to assess patients with PH non-invasively.     

Rapid blood clearance and lack of long-term renal toxicity of 177Lu-DOTATATE enables shortening of renoprotective amino acid infusion

Purpose

The aim of the study was to investigate the feasibility of shortening the recommended 4-h renoprotective amino acid infusion in patients receiving peptide receptor chemoradionuclide therapy (PRCRT) using radiosensitizing 5-fluorouracil. We evaluated the clearance of radiopeptide from the blood, long-term nephrotoxicity in patients undergoing PRCRT with the conventional 4-h amino acid infusion and renal uptake in patients receiving an abbreviated infusion.

Methods

The whole-blood clearance of ¹⁷⁷Lu-DOTA-octreotate (LuTate) was measured in 13 patients receiving PRCRT. A retrospective analysis of short-term and long-term changes in glomerular filtration rate (GFR) in 96 consecutive patients receiving a 4-h infusion was performed. Renal LuTate retention estimated using quantitative SPECT/CT in 22 cycles delivered with a 2.5-h amino acid infusion was compared with that in 72 cycles with the 4-h infusion.

Results

LuTate demonstrated biexponential blood clearance with an initial clearance half-time of 21 min. Approximately 88 % of blood activity was cleared within 2 h. With the 4-h protocol, there was no significant change in GFR (1.2 ml/min mean increase from baseline; 95 % CI ?6.9 to 4.4 ml/min) and no grade 3 or 4 nephrotoxicity at the end of induction PRCRT. The long-term decline in GFR after a median follow up of 22 months was 2.2 ml/min per year. There was no significant difference in the renal LuTate retention measured in patients receiving a 2.5-h amino acid infusion compared to those who had a 4-h infusion.

Conclusion

The greatest renal exposure to circulating radiopeptide occurs in the first 1 – 2 h after injection. This, combined with the safety of LuTate PRCRT, allows consideration of an abbreviated amino acid infusion, increasing patient convenience and reducing human resource allocation.     

Suction against resistance: a new breathing technique to significantly improve the blood flow ratio of the superior and inferior vena cava

Objectives

Optimal contrast within the pulmonary artery is achieved by the maximum amount of contrast-enhanced blood flowing through the superior vena cava (SVC), while minimum amounts of non-contrasted blood should originate from the inferior vena cava (IVC). This study aims to clarify whether “suction against resistance” might optimise this ratio.

Methods

Phase-contrast pulse sequences on a 1.5T MRI magnet were used for flow quantification (mean flow (mL/s), stroke volume (Vol) in the SVC and IVC in volunteers. Different breathing manoeuvers were analysed repeatedly: free breathing; inspiration; expiration; suction against resistance, and Valsalva. To standardise breathing commands, volunteers performed suction and Valsalva manoeuvers with an MR-compatible manometer.

Results

Suction against resistance was associated with a significant drop of the IVC/SVC flow quotient (1.63 [range 1.3-2.0] p?p?p?>?0.05).

Conclusions

Suction against resistance caused a significant drop in the IVC/SVC quotient. Theoretically, this breathing manoeuver might significantly improve the enhancement characteristics of CT angiography.

Key Points

? Suction provokes reduction in blood flow in the inferior vena cava. ? Ratio between the inferior and superior vena cava blood flow diminished during suction. ? Manometer used during breathing standardises MR phase-contrast blood flow measurements.     

Accurate assessment of long-term nephrotoxicity after peptide receptor radionuclide therapy with 177Lu-octreotate

Purpose

Renal radiation during peptide receptor radionuclide therapy (PRRT) may result in glomerular damage, a potential reduction of glomerular filtration rate (GFR) and ultimately lead to renal failure. While reported PRRT nephrotoxicity is limited to data derived from serum creatinine—allowing only approximate estimates of GFR—the aim of this study is to accurately determine PRRT-induced long-term changes of renal function and associated risk factors according to state-of-the-art GFR measurement.

Methods

Nephrotoxicity was analysed using ^99mTc-diethylenetriaminepentaacetic acid (DTPA) clearance data of 74 consecutive patients with gastroenteropancreatic neuroendocrine tumours (GEP NET) undergoing PRRT with ¹⁷⁷Lu-octreotate. The mean follow-up period was 21 months (range 12–50) with a median of five GFR measurements per patient. The change of GFR was analysed by linear curve fit. Potential risk factors including diabetes mellitus, arterial hypertension, previous chemotherapy, renal impairment at baseline and cumulative administered activity were analysed regarding potential impact on renal function loss. In addition, Common Terminology Criteria for Adverse Events (CTCAE) v3.0 were used to compare nephrotoxicity determined by ^99mTc-DTPA clearance versus serum creatinine.

Results

The alteration in GFR differed widely among the patients (mean ?2.1?±?13.1 ml/min/m² per year, relative yearly reduction ?1.8?±?18.9 %). Fifteen patients (21 %) experienced a mild (2–10 ml/min/m² per year) and 16 patients (22 %) a significant (>10 ml/min/m² per year) decline of GFR following PRRT. However, 11 patients (15 %) showed an increase of >10 ml/min/m² per year. Relevant nephrotoxicity according to CTCAE (grade ≥3) was observed in one patient (1.3 %) with arterial hypertension and history of chemotherapy. Nephrotoxicity according to serum creatinine was discordant to that defined by GFR in 15 % of the assessments and led to underestimation in 12 % of patients. None of the investigated factors including cumulative administered activity contributed to the decline of renal function.

Conclusion

Serious nephrotoxicity after PRRT with ¹⁷⁷Lu-octreotate is rare (1.3 %). However, slight renal impairment (GFR loss >2 ml/min/m² per year) can frequently (43 %) be detected by ^99mTc-DTPA clearance assessments. Cumulative administered activity of ¹⁷⁷Lu-octreotate is not a major determinant of renal impairment in our study.     

Portal hypertension in patients with cirrhosis: indirect assessment of hepatic venous pressure gradient by measuring azygos flow with 2D-cine phase-contrast magnetic resonance imaging

Objectives

To measure azygos, portal and aortic flow by two-dimensional cine phase-contrast magnetic resonance imaging (2D-cine PC MRI), and to compare the MRI values to hepatic venous pressure gradient (HVPG) measurements, in patients with cirrhosis.

Methods

Sixty-nine patients with cirrhosis were prospectively included. All patients underwent HVPG measurements, upper gastrointestinal endoscopy and 2D-cine PC MRI measurements of azygos, portal and aortic blood flow. Univariate and multivariate regression analyses were used to evaluate the correlation between the blood flow and HVPG. The performance of 2D-cine PC MRI to diagnose severe portal hypertension (HVPG?≥?16 mmHg) was determined by receiver operating characteristic curve (ROC) analysis, and area under the curves (AUC) were compared.

Results

Azygos and aortic flow values were associated with HVPG in univariate linear regression model. Azygos flow (p?<?10^-3), aortic flow (p?=?0.001), age (p?=?0.001) and presence of varices (p?<?10^-3) were independently associated with HVPG. Azygos flow (AUC?=?0.96 (95 % CI [0.91–1.00]) had significantly higher AUC than aortic (AUC?=?0.64 (95 % CI [0.51–0.77]) or portal blood flow (AUC?=?0.40 (95 % CI [0.25–0.54]).

Conclusions

2D-cine PC MRI is a promising technique to evaluate significant portal hypertension in patients with cirrhosis.

Key Points

? Noninvasive HVPG assessment can be performed with MRI azygos flow. ? Azygos MRI flow is an easy-to-measure marker to detect significant portal hypertension. ? MRI flow is more specific that varice grade to detect portal hypertension.