CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 5, November/December 2023 322 AFRICA found the catheter in the LIMV during dissection of the LIMA. The vessel lumen was intact and no complication was encountered. After completion of dissection of the LIMA, the catheter was repositioned safely into the innominate vein. CABG was completed without additional complications. Case report 4 The LIJV was used for catheterisation in a 61-year-old male patient scheduled for cannulation of the right subclavian vein prior to cardiopulmonary bypass. A high CVP of 24–25 cm H2O was measured in the patient and free blood aspiration was achieved from all the lumens of the catheter. The high CVP was considered to be secondary to moderate portal hypertension detected in the pre-operative period and the patient was also found to be partially dehydrated. The surgeon found the catheter in the LIMV during dissection of the LIMA. The catheter was withdrawn by the surgeon and repositioned under surgical supervision. Discussion The CVC procedure is one of the most frequently performed invasive interventions, not only in anaesthesiology and intensive care units but also in various specialisations from oncology to emergency medicine. This widespread use has resulted in undesirable consequences, such as the perception that complications are normal and acceptable.1 Although complication rates are varied in the literature, the rates of infection, haematoma and pneumothorax are reported at 5–26, 2–26 and 30%, respectively.2 Another less common complication with CVC is malposition of the catheter tip in an incorrect location and it has been reported in approximately 7% of cases.2 The causal mechanism of malposition is multifactorial and not entirely clear. Some studies have shown that direction of slope of the needle facilitates the orientation of the guide-wire to the desired target.4 On the other hand, some researchers have advocated that structural properties of the body such as obesity and extremely large chest size increase the risk for malposition.5 In fact, an approximately 9-mm displacement of the catheter tip has been demonstrated during breathing, particularly expiration.6 Other researchers have stated that misorientation depends on variations in the venous anatomy. These variations lead to malposition by causing misorientation of the catheter tip towards the low-resistance aberrant vessel arms. Venous malformation may be congenital or acquired.7 Congenital variations are usually asymptomatic and can be detected radiologically, which is frequently performed for control after catheterisation. They may complicate radiological detection of the accurate localisation of the catheter tip. The most common congenital variation is persistent left vena cava. It is encountered in 0.3 and 4.3% of healthy patients and those with congenital heart disease, respectively.8 No congenital vascular anomalies were found in our case series. In contrast to the IMV normally originating from the subclavian artery, the IMV may originate from the internal innominate vein. It should be borne in mind that different variations of the IMV may be present.9 The entry orifice of the LIMV is more distant from the veins on the right side, therefore this vein can be reached only by a catheter coming through the left brachiocephalic vein. In patients with portal hypertension, increased blood pressure may enlarge the IMV from the collateral circulation.10 Consequently, that increases the risk for malposition of the catheter. Liminal portal hypertension was present in our fourth patient and that may be one of the possible causes of the malposition. Acquired malformations are more commonly seen than congenital variations. Malformations may have an internal or external origin.11 More than 85% of the vascular distortions with an external origin are associated with malignancy (lung or breast cancer, lymphoma, germ cell tumour). Benign factors include substernal goiter, thymoma, cystic hygroma and histoplasmosis. Atelectasis and pleural fluid can also push or pull venous structures away from the midline. Internal factors are more commonly vascular thrombosis and stenosis. Recent surgical treatment, malignancy, immobilisation, haemodialysis, chemotherapy and pregnancy increase the risk for thrombosis. Likewise, excessive use of a vessel, subclavian catheterisation and interventions performed from the left side of the neck may cause frequent vascular stenosis.12 None of these factors was found in our patients. Malposition with CVC occurs much more frequently after procedures performed in the left side of the neck (internal jugular or subclavian vein). Schummer et al. carried out a prospective study involving 1 794 catheterisations performed by experienced practitioners and found a malposition rate of 6.7%. The malposition rates for the LIJV, right subclavian vein, left subclavian vein and RIJV were 12, 9.3, 7.3 and 4.3%, respectively.13 It has also been found in other studies that malposition in left-sided catheterisation is higher than in those performed from the right side.14 The higher malposition rate in interventions performed from the left side is because of the much longer left brachiocephalic vein compared with the right brachiocephalic vein, more oblique position of the heart and greater number of small vascular branchings in that region.15 In addition, there are two perpendicular angles en route from the LIJV to CVC.3 The intervention was performed through the LIJV due to mandatory reasons in two patients in our case series. Under normal circumstances, the right side would primarily be Fig. 1. Catheter in the left internal mammary vein.
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