Subcutaneous infusion of apomorphine for 12 hours per day is an effective means of controlling on-off fluctuations and dyskinesias in patients with advanced Parkinson's disease (PD) resistant to other treatment. 1,2 However, this technique requires reinsertion of the injection needle into the skin of the abdominal wall at least daily. Twenty-five percent of such patients develop unsettling and distressing skin reactions at the injection site, and many of these patients increasingly find that the absorption of apomorphine becomes unpredictable and unreliable. We describe an alternative to subcutaneous delivery of apomorphine, namely, intravenous infusions through a conventional catheter completely implanted into the superior vena cava, as is used for chemotherapy for cancer.
The device (Port-A-Cath, Pharmacia Inc, Milan, Italy) is a totally implantable system composed of a silicone rubber diaphragm housed in a titanium port connected to a polyurethane catheter. Under local anesthesia, the catheter is inserted through a small skin incision under the clavicle into the left suclavian vein (in right-handed patients) and is then maneuvered into the superior vena cava under radiologic control. The proximal end of the catheter is then attached to the titanium port which is embedded in a small subcutaneous pocket under the chest wall. Access is gained by puncturing overlying skin and the rubber diaphragm with a specially designed needle attached to a programmable pump (Cronopar, Cane `, Turin, Italy) which delivers 10 mg/mL apomorphine at an appropriate rate (5-10 mg/hr) sufficient to maintain the patients ''on'' and mobile throughout the infusion. In addition, for optimum benefit, such patients required oral levodopa (approximately 300-600 mg per day in two to four doses). The infusion pump also has a bolus function which can be used to deliver extra doses of apomorphine, if required; an advantage of the intravenous route is that such boluses of apomorphine take effect within minutes. Another advantage is that the dose of apomorphine required for both the infusion and the boluses is less than that needed using the subcutaneous technique resulting in cost savings. Patients should be checked for clotting factors and cardiac function. The rubber diaphragm can be punched up to 3000 times. In practice, the use of this technique in patients with Parkinson's disease required changing the needle every 15 days, which can be done by patients or caregivers themselves. At the same time, the system should be flushed with saline and heparin.
We have treated seven patients with advanced PD using this technique for periods of 1-13 months. They were chosen because they had previously been successfully managed with subcutaneous apomorphine infusion but developed problems with skin and unreliable responses. Switching to the intravenous route restored a predictable response to apomorphine infusion in all cases. Before implantation the patients had been receiving 6.18 mg/hr (standard deviation [SD] 1.73) and after implantation they required 4.25 mg/hr (SD 0.84). We have encountered no problems with this technique; theoretically, there is a risk of infection and thrombosis. However, with careful attention to antisepsis and the use of regular heparin flushing of the system, these have not proved to be a problem so far. Provided longterm safety for this technique can be shown, it may turn out to be the best way of delivering apomorphine infusion in patients with advanced PD.