A worldwide survey on incidence, management and prognosis of oesophageal fistula formation following atrial fibrillation catheter ablation: The POTTER-AF study

AIMS

Oesophageal fistula represents a rare but dreadful complication of atrial fibrillation catheter ablation. Data on its incidence, management and outcome are sparse.

METHODS AND RESULTS

This international multicenter registry investigates the characteristics of oesophageal fistulae after treatment of atrial fibrillation by catheter ablation. A total of 553,729 catheter ablation procedures (radiofrequency: 62.9%, cryoballoon: 36.2%, other modalities: 0.9%) were performed at 214 centers in 35 countries. In 78 centers 138 patients (0.025%, radiofrequency: 0.038%, cryoballoon: 0.0015% (p<0.0001)) were diagnosed with an oesophageal fistula. Periprocedural data were available for 118 patients (85.5%). Following catheter ablation, the median time to symptoms and the median time to diagnosis were 18 (7.75, 25; range: 0-60) days and 21 (15, 29.5; range: 2-63) days, respectively. The median time from symptom onset to oesophageal fistula diagnosis was 3 (1, 9; range: 0-42) days. The most common initial symptom was fever (59.3%). The diagnosis was established by chest computed tomography in 80.2% of patients. Oesophageal surgery was performed in 47.4% and direct endoscopic treatment in 19.8%, and conservative treatment in 32.8% of patients. The overall mortality was 65.8%. Mortality following surgical (51.9%) or endoscopic treatment (56.5%) was significantly lower as compared to conservative management (89.5%) (odds ratio 7.463 (2.414, 23.072) p<0.001).

CONCLUSIONS

Oesophageal fistula after catheter ablation of atrial fibrillation is rare and occurs mostly with the use of radiofrequency energy rather than cryoenergy. Mortality without surgical or endoscopic intervention is exceedingly high.

Unexpected large device related thrombus at 12 months follow-up after left atrial appendage closure

An 89-year-old woman underwent left atrial appendage (LAA) closure (LAAC) in our hospital because of recurrent gastrointestinal bleedings. The first transesophageal echocardiography (TEE) follow-up at six weeks revealed a complete sealing of the LAA and no device related thrombus. In a TEE follow-up at one year after the LAA closure, a large device related thrombus (6 × 3 cm) was found. Treated with oral anticoagulation (apixaban) the thrombus showed a partial resolution one year later.

Laser balloon in pulmonary vein isolation for atrial fibrillation: current status and future prospects

INTRODUCTION

Visually guided laser balloon (LB) catheter has been an established modality dedicated for pulmonary vein (PV) isolation in patients with atrial fibrillation. The newly updated version of this novel device has technically evolved recent years.

AREAS COVERED

This review will summarize the contemporary technical evolution of LB catheter. Available efficacy outcomes and the historical change of ablation style will be evaluated. Furthermore, the future perspectives for clinical practice are discussed.

EXPERT COMMENTARY

The initial LB ablation system provided comparable clinical results in PV isolation with other technologies, but with a unique strategical concept enabling the direct visualization of the tissue to cauterize. With multigenerational development, the LB catheter has been equipped with more compliant balloon for favorable PV occlusion and a robotically motor driven continuous ablation mode (RAPID mode). These technical innovations changed the concept of the ablation strategy using LB catheter as 'point-by-point' into 'single-shot' fashion. The remaining tasks are further improvements such as equipping with real-time recording system of intracardiac electrogram, durable structured balloon and the instrument for visualizing the cauterization area in a 360-degree panoramic view, which includes potential possibilities to develop this novel device to the more optimal device for PV isolation.

Percutaneous left atrial appendage closure in the presence of thrombus: A feasibility report

BACKGROUND

Patients with a left atrial appendage thrombus (LAAT) despite oral anticoagulation (OAC) are at high risk of thromboembolism (TE) and a relevant proportion of LAAT do not resolve under continued OAC. Left atrial appendage closure (LAAC) in the presence of LAAT was anecdotally described as a therapeutic option to prevent TE in the patients.

OBJECTIVE

To describe the feasibility of LAAC despite LAAT in consecutive patients.

METHODS

We searched the LAAC database of our center to identify patients in whom a LAAC was performed despite evidence of a thrombus in the LAA. All procedures were performed under transesophageal echocardiography guidance, no angiographies were performed to avoid LAAT dislocation. An Amulet Occluder device was preferred to allow proximal implantation and sealing of the LAA.

RESULTS

Nine patients were identified. The mean age was 68.1 ± 10.7 years, four were female, mean CHADSVASC and HASBLED were 3.6 ± 1.7 and 3.0 ± 1.0. Eight of nine patients were on OAC, one patient was under lone aspirin therapy because of bleeding. The mean distance between the LAAT and the estimated landing zone was 18 ± 6 mm, the minimal distance was 11 mm. The mean landing zone was 21 ± 3 mm, devices with a mean size of 25 ± 4 mm were chosen for implantation. All implantation succeeded, only two patients required an intraprocedural replacement. No procedural complication nor short term thromboembolic complication during a follow up of 138 ± 149 days were recorded.

CONCLUSION

In the presented series a percutaneous LAAC despite a LAAT resulted to be feasible and safe.

Complications From Left Atrial Appendage Exclusion Devices

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and has been identified as an independent risk factor for stroke. Prevention of thromboembolic events has been based on oral anticoagulation (OAC) using Vitamin K antagonists (VKA). However, long-term OAC medication is limited by an increased bleeding risk and a low patient compliance. Relying on the observation that the majority of cardiac thrombi originate from the left atrial appendage (LAA) different devices aiming for LAA closure have been proposed. This review will discuss contemporary LAA closure devices with special emphasis on procedure related complications.

An automated method for cell-free layer width determination in small arterioles

Histogram-based thresholding techniques utilized for cell-free layer width measurement in arteriolar flow may produce an overestimation of the layer width since they do not consider faint shaded regions near the vessel wall as part of the erythrocyte column. To address this problem, we developed a new method for detecting the boundary of the erythrocyte column based on an edge detection algorithm. This automated method (grayscale method) provides local detections of the inner vessel wall as well as the boundary between the cell-free layer and the erythrocyte column without binarization of grayscale images. The cell-free layer width measurements using the grayscale method and existing techniques (minimum method and Otsu's method) were compared with those determined manually in arteriolar flows of the rat cremaster muscle. In the absence of the shaded regions, values obtained by the grayscale method and minimum method were statistically in good agreement with the manual method but not in the case of Otsu's method. When the faint shaded regions were present, the grayscale method appeared to produce more accurate results than the minimum method and Otsu's method.

Catheter-ablation of ventricular tachycardia in patients with coronary artery disease: influence of the endocardial substrate size on clinical outcome

Ablation of symptomatic ventricular tachycardia (VT) in patients with coronary artery disease is frequently performed using the three dimensional mapping system CARTO. In the amplitude map, bipolar potentials of <1.5 mV are considered abnormal and represent damaged myocardium due to previous infarction. This pathological electrical area can be arrhythmogenic, serving as the substrate for reentrant VT. The purpose of this study was to correlate the size of the endocardial substrate with the success of VT catheter ablation. Included in this retrospective analysis were 69 consecutive patients with coronary artery disease who underwent ablation for symptomatic clinical VT using CARTO. The voltage maps were analyzed and the area with abnormal bipolar electrograms (<1.5 mV) was determined using geometric approximation models. The area of abnormal electrograms was divided into three sizes: small (<or=15 cm(2); 11 patients), medium (16-99 cm(2); 50 patients), and large (>or=100 cm(2); 8 patients). Patient characteristics were not different between the three substrate groups in regard to age, tachycardia cycle length, or number of radiofrequency applications, however differed significantly between the small, medium and large group in regard to left ventricular ejection fraction (44 +/- 12% vs. 32 +/- 9% vs. 21 +/- 7%, respectively; P = 0.001). Overall, there was a significant correlation between myocardial infarction locations and endocardial substrate sizes (P = 0.031), such that 73% of small substrates were found after inferior myocardial infarctions, and 100% of large substrates after anterior and multiple myocardial infarctions (P = 0.003). After ablation, inducibility of ventricular arrhythmias was more rare in patients with small substrates compared to patients with medium or large substrates (small substrates: 9%, medium and large substrates: 43%, P = 0.043). Although during follow-up of 25 +/- 17 months (1 day to 72 months) there was no significant difference between endocardial substrate sizes in regard to recurrence rates (small: 27%, medium: 38%, large: 50%, P = 0.588), patients with a small substrate did not have fast VT or ventricular fibrillation (VF), in contrast to 30% and 38% of patients with medium and large substrates, respectively. We conclude that in patients with coronary artery disease a small area of low amplitude bipolar potentials (<or=15 cm(2)) was seen more often after inferior myocardial infarction than after anterior and multiple infarctions. After ablation, patients with small substrates were rarely inducible and showed a more benign course during follow-up (trend towards fewer arrhythmia recurrences and no fast VT or VF). As a result smaller arrhythmogenic substrates appear to be better amenable to catheter ablation than larger substrates.

???Shine Through??? on Dual Tracer Parathyroid Scintigraphy: A Potential Pitfall in Interpretation

Dual tracer scintigraphy has become the procedure of choice for preoperative localization of parathyroid adenomas. The typical protocol used by most laboratories is to initially perform a Tc-99m sestamibi (MIBI) study with early and delayed (2-3 hours) washout phase images. This is followed by a thyroid-specific Tc-99m pertechnetate study. A potential pitfall exists if the delayed phase of the initial MIBI study shows an intense, abnormal focus of retention. This focus may interfere with interpretation of the subsequent pertechnetate study because of a "shine through" effect. To differentiate a parathyroid adenoma from a thyroid adenoma, it may be necessary to repeat the thyroid-specific pertechnetate scan on a separate day after the dual tracer study.

Flail aortic valve and acute aortic regurgitation due to spontaneous localized intimal tear of ascending aorta

This report describes the transesophageal echocardiographic findings of acute severe aortic regurgitation resulting from localized transverse intimal tear of ascending thoracic aorta which could not be suspected as a cause of flail aortic valve preoperatively. In patients with chest pain and acute aortic regurgitation associated with flail aortic valve, localized intimal tear of aorta should be considered as a possible cause of flail aortic valve.

Survival and prognostic factors in patients with primary pulmonary hypertension

OBJECTIVES

Primary pulmonary hypertension (PPH) that affects predominantly young and productive people is a progressive fatal disease of unknown cause. The objectives of this study were to characterize mortality in patients with PPH and to investigate the factors associated with their survival.

METHODS

Thirteen patients with PPH were enrolled between 1988 and 1996 and followed-up through July 1999. Measurements at diagnosis included hemodynamic and pulmonary function variables in addition to information on demographic data and medical history.

RESULTS

1) The mean age of the patients with PPH enrolled into the study was 36.1 +/- 9.3 years with female predominance. 2) The estimated median survival was 3.4 +/- 0.6 years. 3) Decreased cardiac index was the only significant predictor of mortality (Cox proportional hazards model).

CONCLUSION

Patients with PPH have a poor survival expectancy. In this limited study with a small number of patients, mortality is largely associated with decreased cardiac index.

Apoptosis in dilated cardiomyopathy

OBJECTIVE

Cardiomyopathy, a popular diagnosis that always obscures more than it reveals, nevertheless has several characteristic histological features. These prominently include widespread focal myocardial fibrosis and associated hypertrophy of surviving cardiac myocyte. In fact, focal noninflammatory degeneration (not necrosis) has been demonstrated as a feature of many forms of cardiac hypertrophy. We hypothesized that this loss of myocardial cells in dilated cardiomyopathy (DCMP) may result from cell death by apoptosis.

METHODS

Endomyocardial biopsy specimens from the right ventricles of six patients who suffered from DCMP were studied, and myocardial specimens from two persons who died in motor vehicle accidents were used as negative controls. For identification of apoptosis, immunohistochemistry with terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end-labeling was performed. In addition, apoptosis was confirmed morphologically by confocal laser scanning microscopy with propidium iodide.

RESULTS

Apoptosis, that was represented by an apoptotic index ranging from 19.8 to 25.4%, could be extensively seen in myocytes and also rarely in non-myocytes of interstitium and vascular endothelium. Morphologically, there were a lot of nuclei with clumps of condensed chromatin, suggestive of apoptosis.

CONCLUSION

The present study demonstrated that myocyte loss in DCMP might be mainly due to the apoptosis of myocytes and interstitial cells, rather than inflammation or cell necrosis.

Radionuclide renal scan findings in rupture of the ureter: a case report

Radionuclide renal scan findings in a patient with iatrogenic rupture of the ureter are reported. Although the literature contains reports of the radionuclide scan in rupture of the ureter from other causes, this, to our knowledge is the first description of the scan findings in iatrogenic rupture.

Exercise renography in untreated subjects with essential hypertension

Exercise induced renal dysfunction is reported to occur in treated hypertensive patients but not seen normotensive subjects. It is unclear if this phenomenon is related to the disease or to treatment.

METHODS

Four normal volunteers and 15 hypertensive subjects (antihypertensive medications were discontinued for more than 4 wk) were studied with upright radionuclide renography at rest and during bicycle exercise. The amount of exercise was sufficient to increase the heart rate at least 20 bpm above the resting value. All subjects were healthy, without evidence of left ventricular hypertrophy renal disease or hypertensive retinal disease. BUN, serum creatinine concentration and urinalysis were normal in all subjects. Renograms were performed for 12-15 min after injection of either 1 mCi[123]orthoidohippurate (OIH) or 2-7 mCi 99mTc-mercaptoacetyltriglycine (MAG3). Visual analysis and mean transit time calculation were performed on the rest and exercise studies.

RESULTS

Seven of 14 hypertensive subjects and none of the normal volunteers demonstrated abnormal prolongation in renal transit during exercise which was not seen on the resting renogram. Four of these seven subjects had a history of hypertension for 2 yr or less.

CONCLUSION

About 50% of individuals with mild-to-moderate hypertension and normal renal function may have abnormal renal transit of renal excretion agents during exercise, although their baseline studies are normal. This finding is unassociated with therapy and appears to be related directly to the pathophysiology of essential hypertension.

Acute renal dysfunction during interleukin-2 treatment: suggestion of an intrinsic renal lesion

Adoptive immunotherapy with interleukin-2 (IL-2) and lymphokine-activated killer (LAK) cells has been effective in treating some advanced malignancies in animals and humans. One complication of this treatment is a reversible, oliguric, acute renal failure, which has been ascribed to renal hypoperfusion and resultant prerenal azotemia. We serially studied renal function in 10 patients receiving high-dose regimens of recombinant interleukin-2 (rIL-2) to attempt to delineate further the nature of the renal dysfunction caused by IL-2 treatment. Renal plasma flow was computed from iodine 131 (I-131 Hippuran; Mediphysics, Paramus, NJ) orthoiodohippurate, excretion curves, and glomerular filtration rate (GFR) was determined by creatinine clearance. Studies done prior to and on day 4 of treatment showed that GFR fell in nine of 10 patients, with a mean decrease of 43% +/- 8%, and renal plasma flow fell in five of the 10 patients with a mean decrease of 5% +/- 10%. The average pretherapy filtration fraction was calculated to be 23% +/- 1% and after 4 days of treatment, decreased to a mean value of 15 +/- 2%. The BUN to creatinine ratio also declined in all patients. These findings collectively suggest that IL-2 nephrotoxicity may result from an intrarenal defect in addition to the previously described prerenal azotemia. Additionally, radionuclide studies of renal function are a reliable and reproducible noninvasive method of assessing these changes in renal function.

Systemic to pulmonary venous shunting in superior vena cava obstruction. Unusual myocardial and thyroid visualization

Obstruction of the superior vena cava is commonly associated with the development of several collateral venous pathways. Right-to-left systemic to pulmonary venous shunting, however, rarely has been reported. This paper describes a case in which a previously unsuspected shunt, manifested by the striking visualization of myocardial and thyroid tissue in addition to other findings, was discovered on a routine lung perfusion scan. Imaging, as well as radiologic studies are presented in the investigation of this phenomenon.

Mechanical responses of tendons to repeated extensions and wait periods

Tendon specimens were repeatedly extended to peak strains of either 2, 3, 4, or 6 percent. During the three 1800 s (30 min.) periods of cyclic extension, the peak loads relaxed with decreases in hysteresis and increases in slack strain. During the two 1800 s wait periods of no extension, the specimens recovered with increases in peak load and hysteresis and decreases in slack strain. However, the recovery during the wait periods was eradicated in the first few subsequent extensions and the relaxation continued as if there were no 1800 s wait periods. Stress-strain responses were well fit with power relations.

Positional effects on distribution of ventilation in chronic obstructive pulmonary disease

Ventilation is distributed predominantly to the dependent lung in normal persons in the decubitus position. We evaluated the distribution of ventilation in four patients with mild-to-moderate chronic obstructive pulmonary disease using 81mKr gas. Patients were tested in the sitting and right and left decubitus positions with and without the application of positive end expiratory pressure (PEEP). In contrast to findings in controls, ventilation was predominantly distributed to the nondependent lung in patients in the decubitus position. Mean ventilation in the right lung decreased from 51% of the total in the sitting position to 31% in the right decubitus position; it increased with the application of 10 cm PEEP. Reduced ventilation in the dependent lung most likely is caused by closure of the airways after a decrease in volume. Application of PEEP resulted in increased lung volume and preferential distribution of ventilation to the dependent lung.

Radionuclide imaging in the nonsurgical treatment of liver and spleen trauma

Twenty-nine patients had splenic or hepatic defects on 99mTc sulfur colloid scintigraphy performed after abdominal trauma. All were treated conservatively. One additional patient had a scan after a laceration was oversewn. Followup scans in 24 patients 1 to 13 months later showed resolution that was complete in nine, partial in 12, and unchanged in three. No defects enlarged. All but two patients were completely asymptomatic; two children with occasional unexplained upper abdominal pain had progressively resolving splenic defects. We conclude that surgery may not always be necessary for liver-spleen injury, that radionuclide imaging is useful in valuation of healing as well as in initial diagnosis, and that the risk of 'delayed' rupture is much smaller than heretofore feared.

Demonstration of traumatic bile leakage with cholescintigraphy and ultrasonography

Technetium-99m HIDA cholescintigraphy and ultrasonography are noninvasive, safe, simple procedures that can document the presence, location, and extent of a bile leak. Early detection of posttraumatic or postoperative biliary tract disruption can significantly reduce morbidity and mortality. The possibility of biliary tract disruption should be considered in any patient who has had blunt or penetrating abdominal trauma. In two cases reported, the new hepatobiliary radiotracer 99mTc dimethyliminodiacetic acid (HIDA) was quite useful in detecting such leaks. Sonography was particularly useful in detecting small intra- or perihepatic bile collections which no longer communicate with the biliary tree. An active bile leak at a surgical anastomosis may also be documented by 99mTc-HIDA cholescintigraphy and can yield information of potential prognostic importance. Serial cholescintigraphy is also useful in evaluating the response to medical or surgical treatment.