PEDIATRIC AND CONGENITAL HEART DISEASE

Original Studies

Vascular Ultrasound Imaging to Study ImmediatePostcatheterization Vascular Complications in Children

Snehal Kulkarni,* MD and Renuka Naidu, MD

Vascular occlusion is the major complication of percutaneous cardiac catheterization inchildren. This is a prospective study to evaluate post catheterization vascular complica-tions in 120 consecutive children with the help of vascular ultrasound and Doppler imag-ing. Ultrasound imaging of both iliac and femoral veins and arteries was done one hourprior and 24 hours after cardiac catheterization. Patients with prior thrombus or occlu-sion of femoral/iliac vein or artery due to previous cardiac catheterization were excludedfrom the study. Age of the patients ranged from 22 days to 12 years with a mean of56 months and weight ranged from 3 to 57 kgs with a mean of 14.3 kgs. Procedure timewas less than 60 minutes in 74 patients (61.66%) and more than 60 minutes in 46 patients(38.33%). 4F sized arterial sheath was used in 108 patients. 5F or bigger sized arterialsheath was used in remaining 12 patients. Incidence of arterial occlusion was higher inpatients weighing less than 10 kgs (16%) as compared with patients weighing more thanl0 kgs (5.5%) {P = 0.031}. Arterial thrombosis was more in infants (16%) as comparedwith older children (7%) {P = 0.203} Prolonged procedure time or use of larger sizedsheath did not have higher incidence of arterial occlusion. Venous thrombosis was foundin 2 patients (1.66%) who had 5F venous sheath. One patient had arterio venous fistula.Our study shows vascular ultrasound imaging can provide anatomical details of femoraland iliac vessels and is a easier and accurate method of assessing postcatheterizationvascular complications in children. ' 2006 Wiley-Liss, Inc.

Key words: vascular complications; postcatheterization complications in children; vas-cular imaging

INTRODUCTION

Arterial thrombosis is the most frequent complicationof percutaneous catheterization in children [1–3]. Afterthe introduction of systemic anticoagulation with heparinin early 1970, the reported incidence of femoral arterialthrombosis following cardiac catheterization decreasedto 0.8–8% [4,5]. The issue of vascular thrombosis andocclusion is gaining more importance as children withcomplex congenital heart diseases need multiple cardiaccatheterizations and interventions [6]. It is important tokeep the vascular patency for further cardiac catheteriza-tions and interventions. The issue of venous thrombosiswas not discussed so far. We discuss the role of vascularultrasound for imaging iliac and femoral vessels indetecting the vascular thrombosis and occlusion.

MATERIALS AND METHODS

This is a prospective study to see for arterial and ve-nous complications during pediatric cardiac catheteriza-

tions with the help of vascular imaging technique. Total120 consecutive patients undergoing diagnostic or thera-peutic cardiac catheterizations over a period of 6 monthswere included in the present study. Ultrasound imagingand Doppler study with color flow mapping of both su-perficial femoral veins and arteries, bilateral external iliacveins and arteries was done by using 5–7 MHz linearphasic array transducer using HP Sonos 5500 equipment.The baseline study was performed 1 hr before cardiaccatheterization. Patients having prior thrombus in the vein

*Correspondence to: Dr. Snehal Kulkarni, Chief of Division of

Pediatric Cardiology, Frontier Lifeline (Dr. K. M. Cherian Heart

Foundation) R-30-C, Ambattur Industrial Estate Road, Mogappair,

Chennai 600102, India. E-mail: kulkarnisnehal15@yahoo.com

Received 4 March 2006; Revision accepted 8 June 2006

DOI 10.1002/ccd.20884

Published online 4 August 2006 in Wiley InterScience (www.interscience.

wiley.com).

' 2006 Wiley-Liss, Inc.

Catheterization and Cardiovascular Interventions 68:450–455 (2006)

or artery or occlusion of femoral/iliac vein or artery dueto previous cardiac catheterization or intervention wereexcluded from the study. All patients had venous and ar-terial accesses during cardiac catheterization. Duringintervention procedures, balloon, balloon/stent assembly,or the device was always advanced through the sheathand not direct percutaneously in the vein or artery. Forthe diagnostic procedures we used 4F sheath for femoralartery and 5F sheath for femoral vein in all the children<12 years of age. For the interventions, the size of thesheath was decided according to the shaft of the balloon,balloon/stent assembly, or device used for intervention.Heparin was given at a dosage of 50 IU/kg during the

procedure. Heparin was repeated with the same dosage ifthe cardiac catheterization time exceeded 60 min. Pe-ripheral pulsations, hematoma at the site of puncture orattempted puncture, and evidence of limb ischemia wascarefully monitored after cardiac catheterization. Ultra-sound imaging and Doppler study with color flow map-ping was repeated after 24 hr or earlier in cases of loss ofdistal pulsations or clinical evidence of limb ischemia.The femoral vein, artery where the access was taken orattempted and the respective iliac vein and artery werestudied.Variables Studied

1. Age2. Weight3. Procedure time4. Sheath size5. Variables were studied with Mann Whitney U test

RESULTS

A total of 120 consecutive patients were studied overa period of 6 months. Age ranged from 22 days to 12

years with a mean of 56 months. Out of 120 patients, 19patients were <1 year of age (15.8%) and 101 patientswere >1 year of age (84.2%). Weight ranged from 3 to57 kg with a mean of 14.3 kg. Thirty six patients were<10 kg (30%) and 84 patients were >10 kg of weight(70%). Procedure time was <60 min in 74 patients(61.66%) and >60 min in 46 patients (38.33%). Twentyeight were interventions and 92 (76.6%) were diagnosticprocedures. 4F arterial sheath was used in 108 patients.5F or bigger sized sheath was used in remaining 12patients. 5F sized venous sheath was used for all diag-nostic cardiac catheterizations. During interventions fromvenous side, size of the sheath was used according to thesize of balloon, balloon/stent assembly, or shaft of thedevice. Absent or diminished arterial pulsations werefound in 10 patients (8%). With ultrasound imaging andDoppler study, out of these 10 patients, 8 (7.6%) hadpresence of thrombus in the artery with significant reduc-tion in arterial blood flow (Figs. 1 and 2). Venous throm-bosis with occlusion of lumen was seen in 2 patients(1.66%) (Fig. 3). Both had 5F venous sheaths. Both thesepatients did not have evidence of arterial thrombosis. He-matoma around the site of puncture was seen in 2patients and 1 patient had arteriovenous fistula (Fig. 4).Procedure time was more than 60 min in 46 patients

and <60 min in remaining 74 patients. There was noincreased incidence of vascular thrombosis with pro-longed procedure time (Fig. 5). At the same time,patients having larger arterial sheaths did not have sig-nificant increased incidence of arterial thrombosis orocclusion (Fig. 6). Only 2 patients had thrombus in thevein. Both had 5F venous sheaths. Age <1 year was asignificant risk factor for developing vascular occlusion(Fig. 7). Though the incidence of arterial occlusion wasmore than twice in children <1 year of age, it was not

Fig. 1. Doppler flow of a thrombosed femoral artery. [Colorfigure can be viewed in the online issue, which is available atwww.interscience.wiley.com]

Fig. 2. Presence of a thrombus in the superficial femoral ar-tery. [Color figure can be viewed in the online issue, which isavailable at www.interscience.wiley.com]

Postcatheterization Vascular Complications in Children 451

statistically significant (P value of 0.263). Childrenweighing <10 kg were at significantly higher risk fordeveloping arterial occlusion. The incidence of vascularocclusion was significantly higher in children weighing<10 kg, which was statistically significant (P value0.031) (Fig. 8). The two patients who developed venous

thrombosis weighed <10 kg. As the number in thisgroup was very small, its statistical significance couldnot be analyzed.Out of 8 patients who had arterial thrombosis, 2

underwent surgical embolectomy during open heartsurgery on the same day. Other 6 patients were treated

Fig. 4. Presence of a arteriovenous fistula between superficialfemoral artery and vein. [Color figure can be viewed in theonline issue, which is available at www.interscience.wiley.com]

Fig. 3. Doppler flow of a thrombosed femoral vein. [Color fig-ure can be viewed in the online issue, which is available atwww.interscience.wiley.com]

Fig. 5. Correlation of thrombotic vascular occlusion and procedural time. [Color figure canbe viewed in the online issue, which is available at www.interscience.wiley.com]

Fig. 6. Correlation of size of sheath with arterial occlusion. [Color figure can be viewed inthe online issue, which is available at www.interscience.wiley.com]

452 Kulkarni and Naidu

with continuous heparin infusion for 24 hr with a doseof 10 units/kg/hr with complete resolution of thrombuson ultrasound imaging and Doppler study. Oral aspirinwas given to 2 patients with venous thrombus for 3months. Ultrasound imaging was repeated after 3 months.There was complete clot resolution in both of them. Thepatient who developed arteriovenous fistula after an inter-vention procedure needed surgical repair.

DISCUSSION

With advancement in cardiac surgeries, children withcomplex heart problems need multiple cardiac catheter-izations or interventions. Repeated cannulations duringcardiac catheterizations and surgeries result in arterial andvenous occlusion [6]. Venous occlusion may remain clini-cally undetected and may become evident during subse-

quent cardiac catheterizations. Long term sequelae of ilio-femoral thrombosis like lower extremity growth distur-bances have been reported in some patients. The presentstudy was undertaken to evaluate immediate post cardiaccatheterization arterial and venous complications with thehelp of vascular ultrasound and Doppler study. We ana-lyzed the incidence of venous thrombosis, which was notdiscussed so far.Several mechanisms have been described for arterial

injury [1–3,7]. There may be formation of thrombusdue to intimal injury resulting from needle, guidewire,or catheter manipulation. Arterial spasm due to intimalinjury also contributes to thrombus formation. In chil-dren with cyanotic heart diseases, change in blood vis-cosity, coagulation parameters, and cardiac output mayplay a role in increased incidence of thrombus forma-tion. Issue of venous thrombosis and occlusion was not

Fig. 7. Correlation of age of the patients vascular occlusion. [Color figure can be viewed inthe online issue, which is available at www.interscience.wiley.com]

Fig. 8. Correlation of weight of the patient with vascular occlusion. [Color figure can beviewed in the online issue, which is available at www.interscience.wiley.com]

Postcatheterization Vascular Complications in Children 453

discussed so far. Similar mechanisms may be responsi-ble for venous occlusion. Smaller children weighing<10 kg are at a higher risk for vascular injury. It maybe due to the small size of femoral artery comparedwith larger catheters. Femoral arteries of small childrentend to constrict around the catheters. Catheter manipu-lation narrows the vascular lumen further. Pressurefrom the large catheter can injure the intima above thepuncture site, which leads to increased potential forthrombosis.Various studies analyzed different predictors for ar-

terial thrombosis. Increased incidence of arterial throm-bosis was found with more number of attempts at arte-rial puncture, absence of back bleed at the end of theprocedure, prolonged duration of procedure, and use oflarger arterial sheaths in the study by Saxena et al. [7].The diagnosis of arterial thrombosis was made on clin-ical evaluation only. They did not find significant dif-ference with different dosage of heparin. The incidenceof arterial thrombosis was 9.3–9.8% in their study.Our incidence of arterial thrombosis (7.6%) is compara-

ble to other studies. Preprocedural status of the femoral ves-sels was not known in any of the previous studies. There isa possibility of vascular occlusion during prior surgery orcardiac catheterization and was attributed to the studiedpopulation, which might have overestimated the incidenceof vascular complications in the previous studies.We excluded the patients who had evidence of arterial

or venous occlusion during prior procedures, so that wecould study the vascular complications related to the pro-cedure only.Incidence of arterial thrombosis was higher in chil-

dren weighing <10 kg and less than 1 year of age inour study. This was comparable to other studies [7–9].Contrary to other studies, procedure time and use oflarger sheaths were not associated with increased inci-dence of vascular complications with us [7]. This maybe due to adequate usage of heparin and repeating thedosage with prolonged procedure time. We did not com-pare the incidence of vascular occlusion in diagnostic vstherapeutic procedures. Therapeutic procedures needlarger sized sheaths and usually have longer proceduretime. We have studied these variables independently.During intervention procedures, balloons, stents, or devi-ces were introduced through the sheaths, not directly per-cutaneously in vein or artery. Neither procedure time northe sheath size was independent risk factors for vascularcomplications in our study.Various techniques have been described for accurate

diagnosis of vascular occlusion [9–12]. Absence of pal-pable lower extremity pulses 3–6 hr after catheter re-moval has been shown to correlate well with femoral ar-terial thrombosis. Imaging of femoral vessels by ultra-sonic method was first described by Sahn et al. in 1982

[12]. They studied total 66 patients. Fourteen patientshad long-term follow-up, i.e., from 4 months to 3 yearsafter cardiac catheterizations. Three out of fourteenpatients had significant differences between vessels onthe catheterized side and uncatheterized sides. In thestudy by Vermillion et al. Doppler evaluation of femoralarteries was done in 19 children after an average age of 2years of balloon dilatation [10]. Out of 19 patients, 3 hadvisible obstructions and 2 had abnormal pulse patterns.All these three children were <1 year of age at the timeof balloon angioplasty. Preprocedural status of the femo-ral vessels was not known in their study.There are lot of advantages of ultrasonic study for

imaging iliac and femoral vessels after cardiac cathe-terizations. The equipment is easily available in all thecenters doing echocardiographies and cardiac catheter-izations. Ultrasonic imaging system appears useful fordefining the position and patency of the vessels. Short-term complications such as spasm, arterial thrombuscan be easily diagnosed, so that early surgical/medicalintervention can be planned if needed. It can provideanatomic and functional information about femoralarteries and veins to aid in planning, performing, andconducting follow up studies. Color flow imaging helpsin detecting disturbed flow in narrowed segments andabsent flow in completely occluded segments. Thestudy can be easily performed with a slightest clinicalsuspicion of limb ischemia. In our study, 10 patientshad clinical evidence of limb ischemia. Out of 10patients, 8 had arterial thrombosis on ultrasound study.Two of them underwent surgical embolectomy duringopen heart surgery on the same day and the remainingreceived intravenous infusion of heparin for 24 hr withcomplete resolution of thrombus. Venous thrombosiswould have been completely undetected on clinicalevaluation as there were no obvious clinical signs ofvenous thrombosis. Similarly femoral arteriovenousmalformation also would have been undetected unlesswe would have looked for it specifically. Presence of col-lateral formation was found in completely occluded ves-sels in others [2]. As only acute occlusions were eval-uated in our study, we could not detect any collateral for-mation. Ours is the only the study where all the patientswho were enrolled in the study were screened for vascu-lar occlusion before cardiac catheterization. Patients hav-ing either venous or arterial occlusion were excludedfrom the study, so that procedure-related vascular com-plications could be studied accurately.Some studies have used MRI to evaluate the status of

femoral and iliac vessels after cardiac catheterization[11,13]. MRI examination has an important advantageover ultrasound study as it includes the length of femoralarteries from the common iliac artery to below the femo-ral bifurcation. Catheter related complications usually

454 Kulkarni and Naidu

involve the external iliac artery. Because of collateralformation, distal common femoral artery and the superfi-cial femoral artery are always patent, even in the pres-ence of complete obstruction of external iliac artery. Thestudy by Burrows et al. demonstrates much higher inci-dence of arterial occlusive changes on MRI after balloondilatation procedure [13]. They did not include all thepatients who underwent balloon dilatation. The patientswho underwent MRI for study of aortic arch were stud-ied for iliofemoral vessels.Our study shows similar incidence of arterial throm-

bosis/occlusion as in others (7.6%). Use of largersheaths or longer procedure time was not associatedwith higher incidence of vascular occlusion. Childrenweighing <10 kg and of <1 year of age were at thehighest risk for developing vascular thrombosis.We conclude that high resolution ultrasound imaging

can provide anatomic and functional information aboutfemoral vessels. This technique can be of assistance inplanning cardiac catheterizations and assessing the shortterm complications of femoral vessel cannulations.

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