Central venous catheter misplacement into an aberrant pulmonary vein: implications of a congenital variation

Editor—Confirmation of the correct position of central venous catheters (CVC) is a major factor in patient safety. Recognising catheter misplacement and, most importantly, inadvertent arterial cannulation, is a crucial step in this process. However, rare congenital venous variations could pose significant difficulties in the interpretation of CVC position criteria, such as pressure waveform, blood gas analysis, and chest radiography.1Gibson F. Bodenham A. Misplaced central venous catheters: applied anatomy and practical management.Br J Anaesth. 2013; 110: 333-346Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar We report an example of an aberrant pulmonary vein as an unexpected cause of CVC misplacement. A 64-yr-old patient with no significant medical history required CVC replacement after abdominal surgery (patient provided written consent for publication). He was mechanically ventilated via tracheostomy, with an FiO2 of 0.5. Although in atrial flutter, he was haemodynamically stable. Left internal jugular vein cannulation was performed under ultrasound guidance. Dark red blood was aspirated under low pressure and the guidewire was passed easily. The operator used ultrasonography to confirm guidewire entry into the internal jugular vein and its course up to the junction with the left subclavian vein before dilation and catheter insertion. We did not perform further ultrasonographic examination of the major thoracic veins or the heart, as there was no suspicion of guidewire misplacement at that time. Catheter tip position was not confirmed by intracardiac electrocardiography, as this technique is not established in our unit. The transduced pressure waveform had a pulsatile triangular shape with a steep upslope, wide base, and no dicrotic notch. This resembled the ‘cannon’ waves observed when the right atrium contracts against a closed tricuspid valve. The mean pressure transduced from the distal lumen of the CVC was 12 mm Hg, implying that the CVC tip was positioned in a blood vessel with venous pressure characteristics. The chest radiograph taken after the procedure revealed that the new CVC followed an unusual, straight course in the left mediastinum (Fig. 1). The image suggests catheter misplacement in the internal thoracic, pericardiophrenic, or accessory hemiazygos vein, or in a persistent left superior vena cava. Surprisingly, blood gas analysis of a sample from the CVC showed oxygenated blood with a Po2 of 29 kPa. This ruled out catheter tip position in a vein and raised a suspicion of inadvertent arterial cannulation. However, the ultrasonographic findings of the guidewire reaching the junction of the left internal jugular vein with the left subclavian vein during insertion, and a mean pressure of 12 mm Hg transduced from the CVC, suggested that arterial location of any part of the catheter was highly unlikely. Although the patient did not have an arterial line, his noninvasive systolic arterial pressure was measured regularly, ranging between 120 and 140 mm Hg during and after the procedure. He was able to communicate and there was no clinical reason to suspect an unrecognised episode of profound arterial hypotension. It was felt that the potential risks of obstructing or damaging the blood vessel cannulated by the catheter would outweigh the benefit of confirming its position before its removal. Additionally, there were other options for central venous access for this patient. Further techniques for determining catheter location or repositioning, such as contrast fluoroscopy, were not considered. The CVC was removed without complications. The conflicting findings surrounding this CVC misplacement suggested a possible pulmonary vein position of the line tip. Our retrospective search showed that the patient already had two recent contrast CT scans reported by two different radiologists. Both of them confirmed an incidental finding of an aberrant connection between the left superior pulmonary vein and the left brachiocephalic vein (the scan reconstruction is provided in the Supplementary material). Furthermore, a radiologist interpreted the chest radiograph as demonstrating the likely position of the line in this aberrant vein. Partial anomalous pulmonary venous connection (PAPVC) is a congenital variation present in 0.04–0.7% of the population.1Gibson F. Bodenham A. Misplaced central venous catheters: applied anatomy and practical management.Br J Anaesth. 2013; 110: 333-346Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar, 2Ho M.-L. Bhalla S. Bierhals A. Gutierrez F. MDCT of partial anomalous pulmonary venous return (PAPVR) in adults.J Thorac Imag. 2009; 24: 89-95Crossref PubMed Scopus (87) Google Scholar, 3Knox S. Madruga M. Carlan S.J. Rare congenital aberrant left superior pulmonary vein discovered with central line placement in a patient with critical cardiorespiratory collapse.Case Rep Pulmonol. 2017; https://doi.org/10.1155/2017/8728904Crossref PubMed Google Scholar, 4Sears E.H. Aliotta J.M. Klinger J.R. Partial anomalous pulmonary venous return presenting with adult-onset pulmonary hypertension.Pulm Circ. 2012; 2: 250-255Crossref PubMed Scopus (39) Google Scholar, 5Inafuku K. Morohoshi T. Adachi H. Koumori K. Masuda M. Thoracoscopic lobectomy for lung cancer in a patient with a partial anomalous pulmonary venous connection: a case report.J Cardiothorac Surg. 2016; 11: 113Crossref PubMed Scopus (2) Google Scholar It is characterised by failure of one or more pulmonary veins to communicate with the left atrium. Instead, the pulmonary vein drains directly or indirectly into the right atrium. Described drainage sites include the superior vena cava, inferior vena cava, right atrium, brachiocephalic (innominate) vein, coronary sinus, and azygos vein1Gibson F. Bodenham A. Misplaced central venous catheters: applied anatomy and practical management.Br J Anaesth. 2013; 110: 333-346Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar,4Sears E.H. Aliotta J.M. Klinger J.R. Partial anomalous pulmonary venous return presenting with adult-onset pulmonary hypertension.Pulm Circ. 2012; 2: 250-255Crossref PubMed Scopus (39) Google Scholar,6Szkorupa M. Bohanes T. Chudáček J. Ctvrtlik F. Anomalous venous drainage of the lung to the brachiocephalic vein.Eur J Cardiothorac Surg. 2013; 44: 768Crossref PubMed Scopus (4) Google Scholar (see diagram in the Supplementary material). Variant pulmonary veins can be unilateral or bilateral. Right-sided origin is more prevalent and is found in 90% of the symptomatic cases.2Ho M.-L. Bhalla S. Bierhals A. Gutierrez F. MDCT of partial anomalous pulmonary venous return (PAPVR) in adults.J Thorac Imag. 2009; 24: 89-95Crossref PubMed Scopus (87) Google Scholar, 3Knox S. Madruga M. Carlan S.J. Rare congenital aberrant left superior pulmonary vein discovered with central line placement in a patient with critical cardiorespiratory collapse.Case Rep Pulmonol. 2017; https://doi.org/10.1155/2017/8728904Crossref PubMed Google Scholar, 4Sears E.H. Aliotta J.M. Klinger J.R. Partial anomalous pulmonary venous return presenting with adult-onset pulmonary hypertension.Pulm Circ. 2012; 2: 250-255Crossref PubMed Scopus (39) Google Scholar PAPVC can be isolated or associated with other findings, such as atrial septal defect and persistent left superior vena cava.2Ho M.-L. Bhalla S. Bierhals A. Gutierrez F. MDCT of partial anomalous pulmonary venous return (PAPVR) in adults.J Thorac Imag. 2009; 24: 89-95Crossref PubMed Scopus (87) Google Scholar,5Inafuku K. Morohoshi T. Adachi H. Koumori K. Masuda M. Thoracoscopic lobectomy for lung cancer in a patient with a partial anomalous pulmonary venous connection: a case report.J Cardiothorac Surg. 2016; 11: 113Crossref PubMed Scopus (2) Google Scholar It is diagnosed by contrast CT scan, cardiac MRI or transoesophageal echocardiography.2Ho M.-L. Bhalla S. Bierhals A. Gutierrez F. MDCT of partial anomalous pulmonary venous return (PAPVR) in adults.J Thorac Imag. 2009; 24: 89-95Crossref PubMed Scopus (87) Google Scholar,4Sears E.H. Aliotta J.M. Klinger J.R. Partial anomalous pulmonary venous return presenting with adult-onset pulmonary hypertension.Pulm Circ. 2012; 2: 250-255Crossref PubMed Scopus (39) Google Scholar If the aberrant venous return is <50% of total pulmonary venous flow, the condition is usually asymptomatic. If there is significant left-to-right shunt, this may manifest as right ventricular overload, increased pulmonary blood flow, increased pulmonary vascular resistance, pulmonary hypertension, and right heart failure.4Sears E.H. Aliotta J.M. Klinger J.R. Partial anomalous pulmonary venous return presenting with adult-onset pulmonary hypertension.Pulm Circ. 2012; 2: 250-255Crossref PubMed Scopus (39) Google Scholar,7Majdalany D. Phillips S. Dearani J. Connoly H. Warnes C. Isolated partial anomalous pulmonary venous connections in adults: twenty-year experience.Congenit Heart Dis. 2010; 5: 537-545Crossref PubMed Scopus (40) Google Scholar Treatment options include pulmonary vasodilators, catheter embolisation, surgical repair, and lung or heart/lung transplant.2Ho M.-L. Bhalla S. Bierhals A. Gutierrez F. MDCT of partial anomalous pulmonary venous return (PAPVR) in adults.J Thorac Imag. 2009; 24: 89-95Crossref PubMed Scopus (87) Google Scholar,4Sears E.H. Aliotta J.M. Klinger J.R. Partial anomalous pulmonary venous return presenting with adult-onset pulmonary hypertension.Pulm Circ. 2012; 2: 250-255Crossref PubMed Scopus (39) Google Scholar,7Majdalany D. Phillips S. Dearani J. Connoly H. Warnes C. Isolated partial anomalous pulmonary venous connections in adults: twenty-year experience.Congenit Heart Dis. 2010; 5: 537-545Crossref PubMed Scopus (40) Google Scholar Understanding the physiological implications of PAPVC in critically ill patients is of significant importance. Because of cardiorespiratory interactions, the left-to-right shunt might become obvious only when mechanical ventilation is discontinued,8Amariei D.E. Reed R.M. Troubleshooting a dialysis line: when blue runs red.BMJ Case Rep. 2018; https://doi.org/10.1136/bcr-2018-225972Crossref PubMed Scopus (1) Google Scholar and its effect on patients with hypoxaemia and hypotension could be more detrimental.3Knox S. Madruga M. Carlan S.J. Rare congenital aberrant left superior pulmonary vein discovered with central line placement in a patient with critical cardiorespiratory collapse.Case Rep Pulmonol. 2017; https://doi.org/10.1155/2017/8728904Crossref PubMed Google Scholar In severe cases, shunt reversal or pulmonary arteriovenous malformations can present with paradoxical embolism.9Porres D. Morenza O. Pallisa E. Roque A. Andreu J. Martinez M. Learning from the pulmonary veins.Radiographics. 2013; 33: 999-1022Crossref PubMed Scopus (71) Google Scholar Our literature search revealed several similar reports of accidental aberrant pulmonary vein cannulation during CVC insertion.3Knox S. Madruga M. Carlan S.J. Rare congenital aberrant left superior pulmonary vein discovered with central line placement in a patient with critical cardiorespiratory collapse.Case Rep Pulmonol. 2017; https://doi.org/10.1155/2017/8728904Crossref PubMed Google Scholar,4Sears E.H. Aliotta J.M. Klinger J.R. Partial anomalous pulmonary venous return presenting with adult-onset pulmonary hypertension.Pulm Circ. 2012; 2: 250-255Crossref PubMed Scopus (39) Google Scholar,8Amariei D.E. Reed R.M. Troubleshooting a dialysis line: when blue runs red.BMJ Case Rep. 2018; https://doi.org/10.1136/bcr-2018-225972Crossref PubMed Scopus (1) Google Scholar,10Alzghoul B. Innabi A. Chada A. Tarawneh A.R. Kakkera K. Khasawneh K. Central venous line insertion revealing partial anomalous pulmonary venous return: diagnosis and management.Case Rep Crit Care. 2017; https://doi.org/10.1155/2017/3218063Crossref Google Scholar Interestingly, most cases were found after left internal jugular vein catheter insertion. Typical findings are unusual appearance of the catheter by chest radiography, oxygenated blood sample, and venous pressure waveform. Most investigators found that Po2 in blood drawn from the misplaced catheters was higher than radial artery samples. This could be because of the right-to-left shunt in the left heart caused by drainage of Thebesian veins. Some authors have described a pulsatile venous waveform, similar to our observation. This was explained by wedging of the line tip, thus allowing for transducing of pulmonary artery pressure.1Gibson F. Bodenham A. Misplaced central venous catheters: applied anatomy and practical management.Br J Anaesth. 2013; 110: 333-346Abstract Full Text Full Text PDF PubMed Scopus (129) Google Scholar,10Alzghoul B. Innabi A. Chada A. Tarawneh A.R. Kakkera K. Khasawneh K. Central venous line insertion revealing partial anomalous pulmonary venous return: diagnosis and management.Case Rep Crit Care. 2017; https://doi.org/10.1155/2017/3218063Crossref Google Scholar PAPVC is an uncommon finding, which can be asymptomatic or undiagnosed. Awareness of this congenital variation would help clinicians to recognise and correctly manage unusual cases of CVC misplacement, and other challenging clinical situations related to this rare condition. The authors declare that they have no conflicts of interest. The following are the Supplementary data to this article: Download .docx (.6 MB) Help with docx files Multimedia component 1 Download .docx (.41 MB) Help with docx files Multimedia component 2