Cardiology registrars and permanent pacemaker complication rates in a district general hospital—safety and service implications

Complications – lead displacement

Compared to the ‘benchmark’ trials used by the HRUK standards for implantation^4-8 (Table 6), we have a higher rate of V-lead displacements. Our A-lead displacement rate of 3.5% was at the upper end of the 0.5%–4.4% range quoted in the literature.^4–8 However, the data in the literature reflect complication rates from more than 10 years ago and the trend since has been for devices to be implanted in a more elderly population with greater co-morbidities.¹² The average age of the patients in the trials quoted in the literature was about 75 years, in comparison to our slightly older cohort of 79 years. Complication rates have also been reported previously to increase with age and with co-morbidities such as left ventricular dysfunction and right ventricular dilatation.¹⁰ It is not possible for us to comment on whether the extent of co-morbidities was similar in our study and in others.

A more recent study, carried out in 2010, reported an overall complication rate of 6.9% for 1,028 PPMs implanted.⁹ The mean age of patients in this study was 77 years, with a range between 17.3 and 99.7 years. Like us, the authors of this study found a V-lead displacement rate (3.6%) that was greater than that for A-lead displacement (2.2%). They reported infection and perforation rates of 0.9% and 0.37%, respectively. They also reported high rates of pneumothorax (4.4%), which were most likely due to the almost exclusive use of the subclavian approach in their cohort. The consistent findings of higher rates of V-lead displacement may reflect a more accurate picture of the complication rates in the DGH today.

Complications: infections

Infections were limited to the surgical site in two cases and were systemic in the other two. All four patients who suffered infections ended up having their devices extracted. In the literature, the time delay before an infection becomes evident can extend even beyond 2 years from implant.¹⁴ Thus, vigilance in the long term is needed. It may be worth noting that none of the four patients who had infections in our study received intrapocket antibiotics, although evidence that the routine use of antibiotic in this way is beneficial is lacking.^13–15

A factor that could contribute to higher infection rates is age and frailty. The ages of our four patients with infections ranged from 82 and 91 years (mean 89 years) and all had significant co-morbidity. Two were bed-bound in nursing homes. There is a theoretical basis for advanced age and impaired wound healing,¹⁶ but only some studies have found age to be a risk factor for infections.^12–15 Other variables that have been consistently associated with higher rates of infection were a previous implant and the absence of prophylactic systemic antibiotics.^12–15

Complications: pneumothorax, perforation and haematomas

Our low rates of pneumothorax in comparison to the other studies reflect our relatively greater usage of the cephalic approach (43% in our cohort). The lack of these complications’ occurrence within the registrar group may be a result of an inherent case-selection bias, with consultants opting to take on more complex cases.

Operator experience

Our study results are consistent with those of a previous study by Aggarwal et al who found that there were no differences in complication rates between inexperienced, defined as one who had performed less than 100 procedures, and experienced operators.⁵ More recently, Eberhardt et al. showed that operators who had performed less than 50 procedures had higher complication rates in patients who were elderly, had left ventricular impairment or right ventricular dilatation.¹⁰ A possible explanation for the difference seen may be the different co-morbid profiles in the different studies. Another plausible explanation would be the different amount of support or supervision inexperienced operators are given in different centres. Nevertheless, our data do show that operations led by registrars working under supervision were as safe as consultant-led ones, and that the training of registrars did not appear to have any adverse impact on patient safety.

Duration of procedure and service provision

An important balance always needs to be struck between training lists and service provision. Our study provides data on the anticipated lengths of time a registrar might take to perform dual or single PPMs using different access routes, which can be factored in when planning lists for training and for service provision. Dual chamber devices take longer to implant (8–10 mins longer for consultants, and 13–29 mins longer for registrars). In addition, it is interesting to see that it took consultants slightly longer to implant all devices when they chose a subclavian approach; for registrars this approach was slightly slower for single-chamber devices. These differences in operating time may be a result of inter operator variability, but they do suggest that, in experienced hands, the cephalic approach does not prolong procedure length significantly and has the added advantage of negating the risk of pneumothoraces.

Limitations

The possibility of case-selection bias might result in reduced complication rates for registrars. As these were all supervised cases, the amount of consultant assistance given to the registrars may inadvertently skew the complication rates in favour of the trainee. Our data also come from a single centre and might not reflect national figures, though recently published data from a high-volume DGH mirror the relatively high lead-displacement rates seen in our study.