CardioVascular and Interventional Radiology

ª Springer Science+Business Media, Inc. 2006 Published Online: 15 June 2006

Cardiovasc Intervent Radiol (2005) 29:997–1002 DOI: 10.1007/s00270-003-0093-y

The Hunter Pulmonary Angiography Catheter for a Brachiocephalic Vein Approach Galia Rosen, Karen J. Kowalik, Suverano Ganguli, David W. Hunter Department of Radiology, University of Minnesota, Minneapolis, Minnesota

Abstract The purpose of this work was to describe our experience in performing pulmonary angiography using the Hunter pulmonary catheter, manufactured by Cook, Inc., which is a modified 6F pigtail catheter with a ‘‘C-shaped’’ curve, designed for a brachiocephalic vein approach. One hundred twenty-three patients underwent pulmonary angiograms using the Hunter catheter between August 1997 and January 2002. Operator comments were gathered in 86 (70%) of the cases. The operator was, if possible, the most junior resident on the service. Thirty-nine operators participated in the survey. Efficacy, safety, and ease of use of the catheter were determined by operatorsÕ comments and ECG observations during the procedure. Corroborating clinical data were gathered from medical records. In 68 (79%) of the procedures that were commented upon, the operator described insertion into the pulmonary artery (PA) as easy; only 2 (2%) indicated difficulty in accessing the PA. In 41 (63%) of the bilateral angiograms that were commented upon, the operator described accessing the left PA from the right PA as easy; only 6 (9%) rated it as difficult and all were with an older technique in which the catheter was withdrawn to the pulmonary bifurcation without a wire or with only the soft tip of the wire in the pigtail and then rotated to the left main pulmonary artery. Thirty-one of the 41 patients who demonstrated premature ventricular contractions (PVCs) had a previous history of heart disease. Nineteen of the 39 patients who did not have PVCs had a history of heart disease (p = 0.018). The maneuverability and shape of the Hunter catheter make pulmonary angiography an easy procedure, even for operators with minimal experience and limited technical proficiency. PVCs demonstrated a statistically significant correlation with a positive patient history for cardiac disease, rather than being a universal risk.

Correspondence to: Galia Rosen; email: [email protected]

Key words: Pulmonary angiography—Catheter and catheterization—Percutaneous brachiocephalic approach

Pulmonary angiography remains the gold standard for diagnosis of pulmonary thromboembolism (PE), although it is usually reserved for cases in which noninvasive studies (i.e., D-dimer levels, Computed tomography angiology (CTA), ventilation/perfusion scans, Magnetic resonance angiograph (MRA), or venous ultrasound) fail to produce unequivocal results. Other than for the diagnosis or treatment of PE, it is also performed in the evaluation of transplanted lungs, pulmonary hypertension, and chronic thromboembolic disease, pulmonary arteriovenous malformations (AVM), hemoptysis, vasculitis, and congenital abnormalities. As CTA and MRA improve, pulmonary angiography has become less frequently performed, which means that the average interventionalist has a steadily decreasing experience with this technically demanding procedure. Therefore, every measure that can make performance easier is becoming even more important. Pulmonary angiography has traditionally been performed with an angled pigtail catheter using a femoral vein approach, and the majority of currently available catheters are designed for transfemoral catheterization [1, 2]. Transfemoral catheterization can pose problems in patients with thrombus in the pelvic veins or inferior vena cava, and because of the need for bed rest postprocedure, the transfemoral approach is less convenient in an outpatient setting. In addition to issues relating to the access site, maneuvering the catheter through the right heart is also not particularly easy from the femoral approach, even for experienced operators. Transbrachial, transaxillary, and transjugular approaches have been proposed to circumvent such problems [3–5]. The Hunter catheter, a moderately high-torque pigtail catheter with a ‘‘C-shaped’’ curve that facilitates passage through the heart and pulmonary arteries (Fig. 1) is designed to be used from a brachiocephalic vein approach.

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Fig. 1. The catheter is advanced to the right ventricle through the tricuspid valve. If the catheter is pointed to the left and slightly anterior, the pigtail and the primary curve tend to pass spontaneously toward the pulmonary valve.

Materials and Methods Catheter Design and Insertion Technique Catheter efficacy and ease of use for pulmonary angiography was determined by recording the operatorsÕ comments and ECG observations at the time of the procedure. Corroborating clinical data were gathered from medical records. In cases where a study coordinator was not present at the time of the procedure, the procedural data were gathered from discussions with the operator, nurse, and technologist in the case and the radiological report of the case. The operator was chosen, if possible, to be someone who had no prior experience with the catheter. This often meant the most junior resident on the service. The Hunter catheter is a modified 6F pigtail catheter. It has a 40
primary curve 1 cm from the pigtail, followed 5 cm thereafter by a 90
secondary curve, and followed 6 cm distally by a 45
tertiary curve, which creates a C shape. Six side holes are located in and just proximal to the pigtail. The catheter is 65 cm long for

1

The procedures were regularly done through a vascular sheath both to enhance the safety of the IJ access (as is the standard of care in our institution) and to enable use of the same access for multiple purposes; often the pulmonary arteriogram was followed by either placement of an IVC filter, a triple lumen central line, and so forth.

G. Rosen et al.: Hunter Pulmonary Angiography Catheter

the internal jugular (IJ) approach and 90 cm long for the brachial (preferably left) vein approach. (See Fig. 1.) In a typical case, the catheter is placed into the right atrium through a 6F internal jugular vein introducer sheath.1 Pressures are measured and the catheter is turned toward the tricuspid valve. The catheter is advanced through the tricuspid valve, usually without resistance, while still connected to the pressure tubing and without a guidewire in place (Fig. 1). After right ventricular pressures are measured, a floppy-tipped guidewire is reinserted so that the tip is near the start of the pigtail (Fig. 2) (Fig. 3) and the catheter is advanced through the right ventricle toward the pulmonary valve. If the right ventricle is large, advancing the wire just far enough to partially open the pigtail will also open the catheter curve. If the right ventricle is small, withdrawing the wire slightly can close the curve.2 The catheter usually passes through the right ventricle without resistance and without dysrhythmia, and through the pulmonary valve and the main pulmonary artery into the right pulmonary artery (Fig. 5). Following selective right pulmonary arteriography, the repositioning from the right PA to the left PA is accomplished very easily. The stiff end of a floppy 0.35 Bentson wire is inserted so that the end is just proximal to the pigtail.3 The pigtail is withdrawn into the main pulmonary artery, and with all curves having been straightened out by the stiff end of the wire, the catheter almost always can simply be pushed forward into the left pulmonary artery (Fig. 4, Fig. 6). Operators who did not use the stiff end of the wire often found this maneuver to be the most difficult part of the procedure, requiring either a counterclockwise torque followed by a quick push or advancing the wire (floppy end) out of the catheter and into the left pulmonary artery, and following with the catheter. Frequently with the floppy-end technique and rarely with the stiff-end technique, the pigtail was withdrawn to a position near the pulmonary valve, and the torque on the catheter might have pushed the catheter against the wall of the pulmonary outflow tract, which resulted in brief dysrhytmias.

Patients One hundred twenty-three patients underwent pulmonary angiograms using the catheter at the University of Minnesota medical center. Of these 123 patients, 73 (59%) patients were female and 50 (41%) patients were male. Ages ranged from 20 months to 82 years. The average age was 46.3 years. Eighteen patients had unilateral pulmonary angiograms (12 right pulmonary angiograms and 6 left pulmonary angiograms) and 105 patients had bilateral pulmonary angiograms. The indications for the study were to evaluate for acute PE in 100 (81%), chronic PE in 4 (3%), pulmonary hypertension in 7 (6%), AVM in 5 (4%), transplant pulmonary artery stenosis in 4

2 The manipulation with a guidewire adjusting the curve of the catheter to different sizes of the right ventricle does require a slightly higher degree of knowledge in interventional technique and anatomy; however, this was not needed in the usual case. 3 The stiff end is inserted as it is. There is no need to curve it or manipulate it in any way. The stiff end of other wires can also be used for that purpose, if those are available to the operator for other reasons, such as a glidewire or a 0.38 wire, but there is no need for any particular wire for that. The vast majority of the procedures that are described in this series were done using a 0.35 Bentson wire.

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G. Rosen et al.: Hunter Pulmonary Angiography Catheter

Fig. 2. A floppy-tipped guidewire is inserted so that the tip is near the start of the pigtail (arrow). The secondary curve straightens slightly. The pigtail in cases with normal to largesized ventricles is turned slightly more directly toward the pulmonary valve. If the right atrium and ventricle are small, the guidewire might not be necessary. (3%), and acute hemoptysis in 5 (4%) patients. Three patients (2%) were evaluated for both acute and chronic PE. Pathological findings were found in 59 (48%) of the cases, including acute PE in 21 (17%), chronic PE or thromboembolic disease in 9 (7%), pulmonary hypertension in 15 (12%), AVM in 4 (3%), pulmonary stenosis posttransplant in 3 (2%), hemoptysis localization and treatment in 3 (2%), vasculitis in 2 (2%), AV shunting in 2 (2%), and vascular invasion by a tumor, pulmonary conduit occlusion, and vascular chronic obstruction in one case each 1 (1%). Twentythree (19 %) of the procedures were therapeutic as well as diagnostic, including thrombolytic agent infusion in 5 (4%), embolization in 6 (5%), Swan–Ganz catheter placement in 6 (5%), IVC filter placement in 4 (3%), pulmonary artery biopsy in 1 (1%), and pulmonary anastomotic stenosis angioplasty in 1 (1%).

Operators Of the 39 physicians who participated in the survey, 34 were Radiology residents or fellows and 10 were Interventional Radiology staff physicians (5 participated both as fellows and later as staff). For most of the study period, a questionnaire was packed together with each catheter and was, therefore, available to the operator upon completion of the case. The earlier and later

Fig. 3. Simple advancement of the catheter will usually push the pigtail through the pulmonary valve. If necessary, the guidewire (arrow) can be advanced into the pigtail to straighten the primary curve further.

packages, however, did not include the questionnaire and these cases were included in the survey only if the dictated and written report on the procedure included the information. This tended to depend on the operatorÕs awareness of the study and the workload.4

Results Pulmonary angiograms using the Hunter PA catheter were successfully performed in 121 of the 123 times they were attempted (98%). In one case, the 90-cm catheter was not available and the 65-cm catheter was slightly too short to advance into the left PA, from a left brachial vein access. In the other case, the Hunter catheter was one of several different catheters that were tried from a femoral approach until finally a Grollman catheter was successful. Of the 123 procedures, 103 (83%) were done using a right IJ vein approach, all of which were successful. Nine (7%) procedures

4 The younger operators were indeed very well supervised by experienced attending physicians. However, they performed the pulmonary angiogram as truly hands-on primary operators and commented on their experiences with the procedure.

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Fig. 4. The catheter passes through the pulmonary valve and the main pulmonary artery into the right pulmonary artery.

used the right common femoral vein approach, five (4%) used the left IJ vein, 1 (1%) used the left common femoral vein, 1 (1%) used the right external jugular vein, 1 (1%) used the left basilic vein, 1 (1%) used the right basilic vein, 1 (1%) used the right subclavian vein, and 1 (1%) used the left brachial vein. Eighty-six users reported on the ease of insertion through the right atrium and right ventricle into the PA. Sixty-eight (79%) users described the insertion through the right atrium and right ventricle into the PA as easy, 16 (19%) reported accessing the PA with moderate ease, and 2 (2%) indicated difficulty in accessing the PA. Sixty-six operators indicated the number of attempts needed to access the PA. Forty-six (70%) operators indicated accessing the PA with 1 attempt, 11 (17%) indicated accessing the PA with 2 attempts, 7 (11%) indicated accessing the PA with few attempts, and 1 (1%) indicated accessing the PA after multiple attempts. One (1%) pulmonary artery could not be accessed because it was thrombosed. In 105 cases of bilateral pulmonary angiograms, 65 operators responded to the question about the ease of accessing the left PA from the right PA. Forty-one (63%) operators rated moving from the right PA to the left PA as easy, 18 (28%) described the maneuver as mildly or moderately difficult, and 6 (9%) described the maneuver as difficult. Almost all of the moderately difficult and

G. Rosen et al.: Hunter Pulmonary Angiography Catheter

Fig. 5. The stiff end of a floppy wire is inserted just proximal to the pigtail. The pigtail is withdrawn into the main pulmonary artery, and with all curves having been straightened out by the wire, the catheter almost always can simply be pushed forward into the left pulmonary artery. Counterclockwise rotation can be added if needed.

difficult cases occurred before the switch to using the stiff end of the wire to straighten the catheter. Catheter stability during injections was reported as excellent, very stable, or good in 78 (87%) procedures; only 3 procedures reported the catheter backing out of the LPA during the injection. The presence or absence of premature ventricular contractions (PVCs) was recorded in 81 of the procedures. PVCs were noted in 42 patients, 31 of whom had prior evidence of cardiopulmonary pathology (19 with pulmonary hypertension, 4 with Chronic Obstructive Pulmonary Disease (COPD), 4 with cardiomyopathies, 2 with arrhythmias, 1 with pericarditis, and 1 with vena cava thrombosis and PE). PVCs were not observed in 39 patients, 19 of whom had prior evidence of cardiopulmonary pathology (9 with pulmonary hypertension, 6 with cardiomyopathies, and 4 with COPD). Using the Fisher Exact Test in a 2 · 2 contingency table, the p-value for the association of PVC during catheter placement and cardiopulmonary pathology was 0.018. There were no problems removing the catheter or with any of the puncture sites. There were no immediate complications during any of the procedures.

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G. Rosen et al.: Hunter Pulmonary Angiography Catheter

Fig. 6. The catheter is then advanced into the left main pulmonary vein.

Discussion Most of the available pulmonary angiography catheters are designed for the femoral approach. This might be due to the fact that they were developed when invasive studies were the main way of diagnosing thromboembolism and before the era of ultrasound-guided IJ puncture [1, 6, 10]. As ultrasound-guided venous access has become a routine part of interventional practice, its advantages can be translated to catheter and access site selection for pulmonary artery studies. The brachiocephalic approach has the advantages of bypassing possible thrombosis in the femoral or iliac veins or inferior vena cava, and it does not require patient bed rest postprocedure. In addition, many patients appear to favor a brachial vein puncture, particularly over a puncture in the groin. More importantly, with the appropriately shaped catheter, accessing the pulmonary arteries can be extremely easy. A standard pigtail with a simple curve [6], as well as a looped guide wire in a ‘‘U’’ curved catheter [7], are techniques that have been described in the past for a brachiocephalic approach. Koizumi et al. [8] developed a 4F curved pigtail catheter to be passed percutaneously from a superficial antecubital vein approach, although the 4F catheter might not allow for high enough flow rates to

adequately define distal pulmonary emboli [9]. Flow-directed catheters are considered relatively easy to place from a groin approach but require a minimum of a 7F delivery system, in comparison to 6F for the Hunter PA catheter, and can occasionally be difficult to advance through the right heart if the cardiac chambers are enlarged or flow is diminished. The design of the Hunter PA catheter allows for easy advancement through the tricuspid valve and right ventricle and into the pulmonary artery, usually without resistance and without guidewire manipulations, which markedly increase PVCs. Adjustment to right ventricular size can be achieved by manipulating the wire position inside the catheter to achieve a more opened or more closed catheter shape. For very large ventricles, the stiff end of the wire can be advanced through the secondary curve to further straighten the catheter and point the pigtail toward the pulmonary valve. It is almost never necessary to advance the guidewire into the right ventricle or outflow tract, which is an important reason for minimizing PVCs. Operator responses and comments have been representative of the superior maneuvering capabilities of the catheter. The repositioning of the catheter from the right PA to the left PA, which was frequently the most difficult maneuver when the catheter was first introduced, has become easy with the adoption of the stiff end of the wire technique. Premature ventricular contractions are a common occurrence during pulmonary angiogram procedures. A correlation between the occurrence of PVCs and evidence of cardiopulmonary pathology was seen. We believe that the occurrence of PVCs could be affected both by the ease of the catheterization and by the propensity of the patient for arrhythmias. The PVCs that occurred were most commonly encountered when the catheter was pushed against the wall of the pulmonary outflow tract. They were frequently single or double PVCs and almost never runs of more than four or five. More experienced radiologists, who understand and have experience with the right ventricle anatomy and how catheters look and feel as they move toward and through the pulmonary valve, might avoid these pitfalls. The angiograms in this series were most often performed by an inexperienced operator, which skews the results toward the worst possible case.

Conclusion The maneuverability and shape of the Hunter catheter make pulmonary angiography an easy procedure, even for operators with minimal experience and limited technical proficiency. Acknowledgments. Disclosure of financial interest - Neither of the authors has any financial interest in the Hunter pulmonary catheter. Dr. D W H designed the catheter that, therefore, was given his name but has no financial relationship with the company and does not receive any royalties from the catheter sales.

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