Extraction of pacemaker and implantable cardioverter defibrillator leads: patient and lead characteristics in relation to the requirement of extraction tools

Effective tools for extraction of pacemaker and ICD leads have been developed in the past decennium. This study investigated the necessity of using these tools in addition to direct traction in relation to patient and lead characteristics. The study encompasses first attempts at extraction of consecutive pacemaker and ICD leads from the subpectoral area. A stepwise extraction protocol was used with traction first (directly or with a locking stylet) followed by laser sheath extraction if not successful. The indication, patient age, time from implant, fixation mechanism, location, and insertion site of the leads were studied in relation to the outcome of traction. A total of 145 leads in 83 patients were extracted. Leads were implanted for 71 +/- 61 months. Indication for extraction was infection in 96 leads and malfunction in 49 leads. There were 90 ventricular leads including 16 ICD leads. Forty-nine (34%) leads were extracted with traction; in 96 (66%) leads a laser sheath was necessary. All leads implanted for < 6 months could be removed with traction alone. In a multivariate logistic regression model, time from implant was the main factor determining success of traction (P < 0.001), but in case of infection the success rate increased (P = 0.004). In conclusion, time from implant is the decisive factor to judge the potential efficacy of lead extraction with direct traction. If leads are implanted for 6 months, the availability of additional extraction tools is necessary when lead extraction is considered. In addition to time from implant, infected leads have a better chance to be removed with traction although it is a much weaker predictor.     

Single Center Experience with Femoral Extraction of Permanent Endocardial Pacing Leads

Between March 1995 and June 1997, 128 leads were extracted from the hearts of 28 women and 50 men, 69 +/- 15 years of age (mean +/- SD, range 22-92 years). The indications for the procedure were: Accufix leads in 18 patients (14%), dysfunction or incompatibility with ICD in 16 (12%), endocarditis on the lead in 41 (32%), pulse generator pocket infection in 28 (22%), and pulse generator and/or lead erosion in 25 patients (19%). The extraction was performed with a snare (lasso), via a femoral vein as a first approach in 116 leads, and as an alternate approach, after extraction from the original site of implantation had failed, in 12 leads. The leads had been implanted for 62 +/- 48 months (range 1-205 months). A Cook sheath was used in 7, and a femoral approach traction in 20 instances. Of the 128 leads, 122 (95%) were completely extracted, and 2 (2%) were partially extracted (the distal electrode remaining attached to the myocardium), and 4 (3%) could not be removed. Four complications occurred: 2 tears of the tricuspid valve without clinical consequences, one separation of the lead's distal electrode which migrated into the hypogastric vein, and one hemorrhage at the femoral puncture site. There was no death or serious complication caused by lead extraction in this series.     

Partial Rupture of the Tricuspid Valve after Extraction of Permanent Pacemaker Leads: Detection by Transesophageal Echocardiography

Traumatic lesions of the tricuspid valve complicating pacemaker lead extractions appear to be rare. We report two cases of partial rupture of the tricuspid valve, following apparently uneventful extraction of permanent ventricular leads, resulting in severe regurgitation and. in one case, chronic heart failure. TEE was useful to identify the traumatic mechanism of tricuspid regurgitation (TR) and the extent of valvular lesions in these patients. Such etiology should be suspected, and TEE performed, in patients developing TR or heart failure late after lead extraction.     

The challenge of endocardial right ventricular pacing in patients with a tricuspid annuloplasty ring and severe tricuspid regurgitation

On occasion, patients with a tricuspid annuloplasty ring may require permanent cardiac pacing. Although it is technically possible to pass a ventricular transvenous lead through a tricuspid valve with an annuloplasty ring, the procedure is complicated by considerable chamber enlargement and mechanical distortion of the tricuspid valve often with severe residual tricuspid regurgitation. Over a 25-month period, transvenous ventricular lead placement following insertion of a tricuspid annuloplasty ring was successfully performed in five patients (three women). The patient mean age was 66 years (range 55-77 years). Four cases had slow atrial fibrillation and another paroxysmal atrial fibrillation requiring His-bundle ablation. Two patients had mitral valve replacement and two aortic and mitral valve replacements. All patients had residual severe to torrential tricuspid regurgitation. Seven ventricular steroid-eluting screw-in leads were used. Single leads were used in three cases, whereas in two others, two ventricular leads were attached to a dual chamber pulse generator. Although technically difficult, ventricular lead placement was successful using standard guidewires with broad curvatures. Satisfactory acute and follow-up stimulation thresholds and sensing were obtained with the only complication being an intraoperative lead dislodgement, prompting a second ventricular lead. Successful transvenous lead placement across a tricuspid annuloplasty ring is possible.     

Severe right ventricular and tricuspid valve dysfunction after pericardiocentesis

Pericardiocentesis is performed to treat cardiac tamponade or diagnose the cause of pericardial effusion. Cardiogenic shock with right ventricular (RV) dysfunction is a rare complication after pericardiocentesis. We report a case of an 82-year-old man who suddenly suffered cardiopulmonary arrest 12 h after pericardiocentesis. A transthoracic echocardiogram showed remarkable RV dysfunction and tricuspid valve dysfunction. Tricuspid valve closure was severely impaired, and the tricuspid regurgitation signal showed laminar flow with an early peak. However, after treatment with high-dose inotropic drugs, hemodynamic parameters gradually recovered. A transthoracic echocardiogram performed 24 h later showed improved motion of the RV and the tricuspid valve, resulting in a reduction in tricuspid regurgitation. RV and tricuspid valve dysfunction after pericardiocentesis needs to be recognized as a critical complication. Physicians also need to pay attention to not only the amount of drainage but also underlying RV dysfunction.     

Color flow Doppler mapping studies of "physiologic" pulmonary and tricuspid regurgitation: evidence for true regurgitation as opposed to a valve closing volume.

Color flow Doppler mapping using either an Aloka 880 or a Toshiba SSH65A system was performed in 39 normal subjects (aged 13 to 45 years) and 43 patients (aged 13 to 82 years) with pathologic tricuspid or pulmonary regurgitation to evaluate the incidence of "physiologic" regurgitation of right heart valves and to determine the differentiating characteristics in the spatial distribution and velocity encoding of "normal" and "pathologic" regurgitant jets. In the normal subjects, tricuspid and pulmonary regurgitation were documented in 32 (83%) and 36 (93%), respectively, and were unrelated to the system being used. Flow acceleration and aliasing were imaged on the right ventricular side of the tricuspid regurgitant orifice and on the pulmonary artery side of the pulmonary valve (in both normal subjects and patients), and indicated flow convergence for true regurgitation through an orifice as opposed to blood being driven retrogradely by the closing valve. Such proximal acceleration was documented in all patients with pathologic tricuspid regurgitation, in 31/32 of the normal subjects with tricuspid regurgitation, and was also observed in 12/15 (80%) of the patients and 4/12 (33%) of normal subjects with pulmonary regurgitation who were examined with the Toshiba system. The dimensions (mean +/- SD) of tricuspid regurgitant jets (length [JL] and area [JA]) were consistently larger in the patients than in the normal subjects [JL: 3.4 +/- 0.9 vs 1.2 +/- 0.5 cm, p less than 0.001; and JA: 5.7 +/- 2.0 vs 1.4 +/- 0.7 cm2, p less than 0.001) as were the pulmonary regurgitation jet dimensions (JL: 1.8 +/- 0.4 vs 0.9 +/- 0.08 cm, p less than 0.001; JA: 1.8 +/- 0.7 vs 0.3 +/- 0.08 cm2, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Tricuspid regurgitation in children: a pulsed Doppler, contrast echocardiographic and angiographic comparison

Thirty-one children with congenital heart disease were examined for tricuspid regurgitation by four methods: (1) auscultation, (2) pulsed Doppler echocardiography, (3) saline contrast echocardiography, and (4) right ventricular angiography. Tricuspid regurgitation was detected in three children by auscultation, in 20 by pulsed Doppler echocardiography, in 21 by saline contrast echocardiography, and in 20 by right ventricular angiography. To determine the prevalence of tricuspid regurgitation in children suspected of having congenital heart disease, we reviewed 5417 Doppler echocardiograms performed between 1983 and 1985. Tricuspid regurgitation was detected in 399 of 4670 children (8.5%) with congenital heart disease and in 26 of 106 newborns (25%) with respiratory distress. By comparison, tricuspid regurgitation was detected in only 19 of 641 (3%) normal children. Tricuspid regurgitation is uncommon in normal children, but its incidence in children with congenital heart disease and/or respiratory distress is high.     

Laser lead extraction: predictors of success and complications

BACKGROUND: Paralleling the rise in pacemaker and defibrillator implantations, lead extraction procedures are increasingly required. Concerns regarding failure and complications remain. METHODS AND RESULTS: A total of 200 lead extraction procedures were performed at the Montreal Heart Institute between September 2000 and August 2005. In 23 patients, all leads were removed by traction with a locking stylet. A total of 270 leads were extracted using a laser sheath system (Spectranectics, Colorado Springs, CO, USA) in 177 procedures involving 175 patients (74% male), age 62+/-16 years. Procedural indications were: infection 88 (50%), dysfunction 54 (30%), upgrade 21 (12%), and other 14 (8%). Overall, 241 leads (89%) were successfully extracted, 7 (3%) were partially extracted (< or = 4 cm retained), and 22 (8%) were non-extractable. In multivariate analyses, predictors of failed extraction were longer time from implant (OR 1.16 per year, P=0.0001) and history of hypertension (OR 5.2, P=0.0023). Acute complications occurred in 14 of 177 procedures (7.9%): 8 (4.5%) minor and 6 (3.4%) major, with one death. In multivariate analyses, the only predictor of acute complications was laser lead extraction from both right and left sides during the same procedure (OR 9.4, P = 0.0119). In addition, 3 of 10 patients with failed or partially extracted infected systems eventually required open chest explantation because of endocarditis. CONCLUSION: Most leads not amenable to manual traction may be successfully extracted by a percutaneous laser sheath system. While most complications are minor, major complications including death may occur. Older leads are at higher risk for failed extraction. Endocarditis may ensue if infected leads are incompletely removed.     

Pacemaker lead prolapse through the pulmonary valve in children

BACKGROUND: Transvenous pacemaker leads in children are often placed with redundant lead length to allow for anticipated patient growth. This excess lead may rarely prolapse into the pulmonary artery and potentially interfere with valve function. We sought to determine the response to lead repositioning on pulmonary valve insufficiency. METHODS: Retrospective reviews of demographics, lead type, implant duration, and radiography and echocardiography. RESULTS: A total of 11 pediatric patients were identified with lead prolapse through the pulmonary valve, of which nine patients underwent procedures to retract and reposition the lead (age at implant 9 +/- 4 years, age at revision 13 +/- 4 years). The implant duration prior to revision was 4 +/- 3 years. Two leads required radiofrequency extraction sheaths for removal, two pulled back using a snare, while five leads were simply retracted and repositioned. Tricuspid regurgitation was none/trivial (three), mild (four), or moderate (two) and only two improved with repositioning or replacement. Pulmonary regurgitation preoperatively was mild (three), mild-moderate (two), or moderate (four) compared with trivial (three), mild (four), and moderate (two) after revision. Patients with longer-term implanted leads had less improvement in pulmonary insufficiency. Two patients had mild pulmonary stenosis from lead-related obstruction. CONCLUSIONS: Prolapse of transvenous pacing leads into the pulmonary artery can occur when excess slack is left for growth. Leads can often be repositioned, but may require extraction and replacement, particularly if chronically implanted and adherent to valve apparatus. Lead revision does not always resolve pulmonary insufficiency, potentially leaving permanent valve damage.     

Permanent pacemaker lead entrapment: role of the transesophageal echocardiography

Numerous complications induced by pacemaker electrodes have been reported. Although mild tricuspid regurgitation is a well-documented complication of transvenous right ventricular pacemaker leads secondary to abnormal valve coaptation, severe tricuspid regurgitation resultingfrom perforation of the tricuspid valve itself is a rare complication. This case report details a patient with severe tricuspid regurgitation secondary to impingement of the tricuspid valve by a permanent pacing lead that was diagnosed by transesophageal echocardiography. Surgical repair was advocated because of symptomatic significant tricuspid regurgitation.     

Lead implant duration does not always predict ease of extraction: extraction sheath may be required at < 1 year

Introduction: Lead implant duration is a predictor of extraction sheath (ES) use in transvenous lead extraction (TLE). Most operators agree that leads with short implant durations can be extracted easily but data regarding defibrillator (implantable cardioverter‐defibrillator [ICD]) leads and newer generation leads with backfilled coils are limited. Methods and Results: We performed a retrospective study of consecutive patients undergoing TLE of leads with implant durations of ≤ 2 years at a single, high‐volume center. Patient and lead characteristics, indications, and ES use were analyzed. Between January 2000 and January 2011, 139 patients underwent TLE meeting inclusion criteria. Mean implant duration was 13.2 ± 6.4 months. The cohort was 67% male with a mean age of 63 years (16–93) and left ventricular ejection fraction of 36 ± 17%. Indications for extraction included infection (51%), lead malfunction (27%), device upgrade (13%), and other indications (venous occlusion, severe chronic pain at site of device or lead, advisory leads, etc., 9%). Extraction was achieved with simple traction alone in 68% of the 239 leads removed. ES assistance with laser or femoral sheaths was employed in 32% of cases. ES use increased significantly with longer implant duration (P = 0.0004). In multivariate analysis, young age, the presence of an ICD, and increasing implant duration were the strongest predictors of the need for ES assistance for successful lead removal. There was no statistically significant difference in ES use between older and newer generation ICD leads (P = 0.68). Conclusions: While leads with short implant durations may be extracted easily, the need for ES assistance is significant and frequently unpredictable even with newer generation ICD leads. Thus, operators should be fully prepared to use all available methods of extraction in every case regardless of implant duration. (PACE 2011; 34:1615–1620)     

Extraction of looped transvenous pacing leads to reduce tricuspid regurgitation

Transvenous leads are a known source of iatrogenic tricuspid regurgitation. It is commonly held that extraction of chronic pacing and defibrillator leads will not reduce this, due to the inevitable trauma to the valve associated with the procedure. We demonstrate three cases of clinically significant reductions in tricuspid regurgitation after extraction of leads that were looped across the tricuspid valve.     

Postmortem analysis of encapsulation around long-term ventricular endocardial pacing leads

OBJECTIVE: To analyze the site and thickness of encapsulation around ventricular endocardial pacing leads and the extent of tricuspid valve adhesion, from today's perspective, with implications for lead removal and sensor location. MATERIAL AND METHODS: Gross cardiac postmortem analysis was performed in 11 cases (8 female and 3 male patients; mean age, 78+/-7 years). None of the patients had died because of pacemaker malfunction. The mean implant time was 61+/-60 months (range, 4 to 184). RESULTS: The observations ranged from encapsulation only at the tip of the pacing lead to complete encapsulation along the entire length of the pacing lead within the right ventricle. Substantial areas of adhesion at the tricuspid valve apparatus were noted in 7 of the 11 cases (64%). The firmly attached leads could be removed only by dissection, and in some cases, removal was possible only by damaging the associated structures. No specific optimal site for sensor placement could be identified along the ventricular portion of the pacing leads; however, the fibrotic response was relatively less prominent in the atrial chamber. CONCLUSION: Extensive encapsulation is present in most long-term pacemaker leads, which may complicate lead removal. The site and thickness of encapsulation seem to be highly variable. Tricuspid valve adhesion, which is usually underestimated, may be severe. In contrast to earlier reports, our study demonstrates that the extent of fibrotic encapsulation may not be related to the duration since lead implantation. Moreover, we noted no ideal encapsulation-free site for sensors on the ventricular portion of long-term pacing leads.     

The importance of tricuspid regurgitation and right ventricular overload in ICD/CRT recipients: beside the left, beyond the left

Device therapy for advanced heart failure has become increasingly employed in the last 10 years. Several retrospective studies have postulated a harmful effect of implantable cardioverter-defibrillator (ICD) lead placement on tricuspid valve function and right heart hemodynamics, in particular among patients with preexisting pulmonary vascular overload and both left and right ventricular remodeling/dysfunction. This functional hypothesis is also supported by long-term clinical follow-up analyses of ICD and cardiac resynchronization therapy recipients. In this viewpoint, we propose that the possibility of worsening tricuspid regurgitation and consequent hemodynamic deterioration following device implantation should be considered in future studies, as well as in the preimplant evaluation of individual candidates among other clinical factors.     

Outcomes and Echocardiographic Follow-up After Surgical Management of Tricuspid Regurgitation in Patients With Transvenous Right Ventricular Leads

ObjectiveTo evaluate outcomes of elective surgical management of tricuspid regurgitation (TR) in patients with transvenous right ventricular leads, and compare results between non–lead-induced and lead-induced TR patients.Patients and MethodsWe studied patients with right ventricular leads who underwent tricuspid valve surgery from January 1, 1993, through December 31, 2015, and categorized them as non–lead-induced and lead-induced TR. Propensity score (PS) for the tendency to have lead-induced TR was estimated from logistic regression and was used to adjust for group differences.ResultsFrom the initial cohort of 470 patients, 444 were included in PS-adjustment analyses (174 non–lead-induced TRs [123 repairs, 51 replacements], 270 lead-induced TRs [129 repairs, 141 replacements]). In PS-adjusted multivariable analysis, lead-induced TR was not associated with mortality (P=.73), but tricuspid valve replacement was (hazard ratio, 1.59; 95% CI, 1.13 to 2.25; P=.008). Five-year freedom from tricuspid valve re-intervention was 100% for non–lead-induced TR and 92.3% for lead-induced TR; rates adjusted for PS differed between groups (P=.005). There was significant improvement in TR postoperatively in each group (P<.001). In patients having tricuspid valve repair, TR grades tended to worsen over time, but the difference in trends was not significantly different between groups.ConclusionLead-induced TR did not affect long-term survival after elective tricuspid valve surgery. In patients with lead-induced TR, tricuspid valve re-intervention was more common. Improvement in TR was achieved in both groups after surgery; however, severity of TR tended to increase over follow-up after tricuspid valve repair.     

Cardiac Pacing in Fetal Lambs: Intrauterine Transvenous Cardiac Pacing for Fetal Complete Heart Block

To evaluate the feasibility of intrauterine transvenous cardiac pacing, the right ventricular output was measured during pacing in six fetal lambs. Under maternal anesthesia, the uterus was opened, and, under local anesthesia, the pacing lead (Medtronic Capsure SP4023) was inserted via the fetal left internal jugular vein. Right ventricular output was estimated using an Aloka SSD-730 ultrasound device, and tricuspid valve regurgitation was evaluated with an Aloka SSD-880 using the transuterine approach. The ultrasonic right ventricular cardiac output was measured under three different conditions: (1) with the tip of the pacing lead in the superior vena cava (control); (2) with the tip of the pacing lead in the right ventricle; and (3) with pacing at 200 beats/min. The right ventricular output decreased when the pacing lead was inserted into the right ventricle, as well as during pacing at 200 beats/min ([1] = 107 ± 13.2 ml/kg per min; [2] = 73.8 ± 17. 5 ml/kg per min; and [3] = 78.3 ± 23.6 ml/kg per min), Tricuspid regurgitation did not change under any of the conditions tested. Intrauterine transvenous cardiac pacing was successfully achieved. Insertion of the pacing lead into the right ventricle decreased the ventricular output without increasing tricuspid valve regurgitation.     

Frequency of Doppler measurable pulmonary artery pressures

The current literature suggests that right-sided heart pressures can be obtained noninvasively in approximately 60% of patients. We hypothesized that with a focused echocardiographic Doppler examination, measurable tricuspid or pulmonary valve regurgitation suitable for measuring pressures could be obtained in a higher percentage of patients. The study group consisted of 200 consecutive patients undergoing echocardiographic and Doppler hemodynamic evaluation. All patients were first examined by an ultrasonographer instructed to attempt to record tricuspid and pulmonary regurgitant velocities. After this examination, a designated cardiologist performed a focused examination with the intent of improving the signal quality and increasing the number of measurable signals for evaluation. Tricuspid regurgitation of measurable quality was recorded in 147 (73.5%) of 200 patients by the ultrasonographer; this result was improved to 172 patients (86%) by the designated cardiologist. Pulmonary regurgitation was obtainable in 147 (95%) of 154 patients and was of measurable quality in 137 (89%). When results of tricuspid and pulmonary regurgitation were combined, a quantifiable signal was obtained in 194 (97%) of 200 consecutive unselected patients. This study demonstrates that a well-trained ultrasonographer or echocardiologist can obtain right-sided pressures in at least 95% of all unselected cardiovascular patients.     

Contributions of Advanced Techniques to the Success and Safety of Transvenous Leads Extraction

Purpose: We measured the proportion of intravascular leads, which can be extracted by simple traction versus with newer techniques, and examined the overall safety and success rate of lead extractions.
Methods: Between January 2005 and December 2007, 311 consecutive patients (mean age = 70 ± 14 years, 79% men) underwent extractions of 250 atrial, 318 ventricular, and 22 coronary sinus leads, in the surgical facilities of two experienced medical centers, under general anesthesia, at a mean of 7.2 ± 5.1 years (range 0.1–27.0) after lead implantation. Infection was the indication for extraction in 67.5% of cases. Complementary techniques were used when simple extraction with a locking stylet was unsuccessful.
Results: Simple traction, with or without a locking stylet, allowed the complete removal in 27.0% (95% confidence interval [CI] 22.1–31.9) of patients. A mechanical sheath, laser sheath, and/or lasso catheter were used in the remaining patients. The overall extraction success rate was 89.7% (95% CI 86.3–93.1). There was one procedure-related death (0.3%; 95% CI 0.0–1.0). Among five other deaths occurring within 10 days after the procedure, four were due to septic shock. Duration of lead implantation was the strongest independent predictor of major adverse events (P = 0.002) and incomplete lead extraction (P = 0.005).
Conclusion: In contrast with simple traction, advanced techniques allowed the complete extraction of nearly 90% of leads. In experienced hands and with surgical back-up, these techniques were safe. Patients presenting with infected implanted cardiac devices suffered a high rate of major adverse despite complete extraction of the lead(s).     

Pacemaker lead extraction with the needle's eye snare for countertraction via a femoral approach

Femoral approach pacemaker lead extraction is described as a safe and efficacious procedure. When the lead can not be removed from its myocardial insertion, the "Needle's eye snare" has become available, and it allows a femoral approach traction associated with a countertraction. Between May 1998 and May 2000, 222 lead extraction procedures were performed in 99 patients using the femoral approach. This article reports the results of the 70 lead extractions requiring the use of the Needle's eye snare for femoral approach countertraction in 39 patients with a total of 82 leads. The indications were infection, accufix leads and lead dysfunction in 56, 1 and 6 leads, respectively. The age of the leads was 113 +/- 56 months. Sixty-one (87.2%) leads were successfully extracted, the extraction was incomplete in 3 (4.3%) cases and failed in 6 (8.5%) cases. The failures were due to leads totally excluded from the venous flow for four leads, the impossibility of advancing the 16 Fr long sheath through the right and left iliac veins for one lead and one traction induced a nontolerated ventricular arrhythmia. In these cases, an extraction by a simple upper traction had been attempted in another center several months before. The complications included two deaths and one transient ischemia of the right inferior limb. Despite the selection of a series of leads for which an extraction by a simple traction on the proximal end of the lead was impossible or unsuccessful, femoral countertraction seems to be a safe and efficacious procedure. The failure of this technique occurred in patients with damaged leads due to a previous extraction procedure performed in centers with limited experience in lead extraction.     

Tricuspid valve insufficiency: what should be done?

Tricuspid regurgitation is relatively common. Due to the progress made in echocardiography, its diagnosis is in general made readily and in reliable fashion. Basically one has to distinguish between functional tricuspid valve regurgitation due to volume and/or pressure overload of the right ventricle with intact valve structures versus tricuspid valve regurgitation due to pathologic valve structures. The clear identification of the regurgitation mechanism is of prime importance for the treatment. Functional tricuspid valve regurgitation can often be improved by medical treatment of heart failure, and eventually a tricuspid valve plasty can solve the problem. However, the presence of pathologic tricuspid valve structures makes in general more specific plastic surgical procedures and even prosthetic valve replacements necessary. A typical example for a structural tricuspid valve regurgitation is the case of a traumatic papillary muscle rupture. Due to the sudden onset, this pathology is not well tolerated and requires in general surgical reinsertion of the papillary muscle. In contrast, tricuspid valve regurgitation resulting from chronic pulmonary embolism with pulmonary artery hypertension, can be improved by pulmonary artery thrombendarteriectomy and even completely cured with an additional tricuspid annuloplasty. However, tricuspid regurgitations due to terminal heart failure are not be addressed with surgery directed to tricuspid valve repair or replacement. Heart transplantation, dynamic cardiomyoplasty or mechanical circulatory support should be evaluated instead.