Panorama

As the global pop­u­la­tion ages, the impor­tance of endo­vascular ther­a­pies con­tin­ues to grow. Studies show that approx­i­mately from 3 to 10% of the pop­u­la­tion in indus­tri­alized countries suf­fer from periph­eral arterial dis­ease (PAD). In 90% of cases, the dis­ease affects the legs. In more than 95% of cases, the dis­ease is caused by arte­rio­scle­ro­sis in which the nar­row­ing of the arteries sev­erely restricts blood flow to the extrem­ities. Some may expe­ri­ence little or no dis­com­fort while blood flow is still ade­quate in the early stages of the dis­ease, but as it pro­gresses, they may expe­ri­ence increas­ing pain in the calf while walk­ing. Often, they must stop until the pain sub­sides before they can con­tinue walk­ing. PAD is also known as ‘win­dow shop­per’s dis­ease’ (inter­mit­tent clau­di­ca­tion) because people with PAD often stop to, sup­pos­edly, look in shop win­dows while walk­ing through town. If PAD is not treated con­sis­tently, it can develop into gan­grene requiring an ampu­tation.

The prob­a­bility of devel­op­ing the dis­ease increases with age. From the age of 70 onwards, the prev­a­lence is around 15 to 20%. Clas­sic risk fac­tors, in addi­tion to age, include nico­tine abuse, arterial hyper­tension, hyper­lip­id­emia, hyper­cholester­olemia, and diabetes mellitus.

The team of vas­cu­lar sur­geons at Giessen Uni­ver­sity Hospital is spe­cial­ized in com­plex open sur­gi­cal ther­a­pies and endo­vascular treat­ment of PAD, and uses both pro­ce­dures for the max­i­mum bene­fit of their patients. Prof. Dr. Johannes Kalder has been the head of vascular sur­gery since 2020. He and his team reg­u­larly oper­ate on patients with PAD, per­form­ing an aver­age of 350 endo­vascular pro­ce­dures on the ves­sels of the lower extrem­ities each year.

Today, Prof. Kalder and his col­leagues PD Dr. Paula Keschenau, chief phy­si­cian for vascular sur­gery, and Anne Lindemann, resi­dent phy­si­cian for vascular sur­gery, are oper­at­ing on just such a case. The patient pres­ented with stage IIb to III PAD. He could only walk 15 meters with­out symp­toms, and was woken up at night by the pain in his foot. He had a stent implanted in his leg for PAD at another clinic years earlier.

The team has been using the Ziehm Vision RFD Hybrid Edition¹ since 2020, and the EndoNaut vascu­lar navi­ga­tion sys­tem² for endo­vascular treat­ment since 2022. The EndoNaut work­sta­tion is also impor­tant for this case. To local­ize the lesion, the team creates pre­oper­ative pan­o­ramic images with the EndoNaut work­sta­tion. The C-arm gen­er­ates fluo­ro­scopic and angi­og­ra­phic images that are trans­ferred to the EndoNaut workstation.

“The combined pano­rama with the under­lying bone makes it easier to deter­mine the loca­tion of the lesion and opti­mally align the C-arm for the inter­vention.”

Cor­re­spond­ing images are stitched together to create the intra­oper­a­tive 2D pan­o­rama. A fluo­ro­scopic pan­o­rama, an angi­og­raphic pan­o­rama, and a com­bined fluo­ro­scopic and angi­og­raphic pan­o­rama are auto­mat­ically gen­er­ated. “The com­bined pan­o­rama with bone over­lay makes it easier for us to deter­mine the posi­tion of the lesion,” con­firms Prof. Kalder. “With this infor­ma­tion, we can opti­mally align the C-arm for the inter­ven­tion.” Dr. Keschenau adds that in the case of multi­ple lesions, it is also pos­sible to avoid repeated angi­og­raphy of indi­vid­ual seg­ments and to tar­get the lesions directly in the pan­o­rama. The sys­tem algo­rithm allows the cre­a­tion of a very pre­cise pan­o­rama, using auto­matic, near real-time 2D-2D regis­tra­tion between adja­cent images with mini­mal over­lap. The team is impressed by the good over­view the pan­o­rama pro­vides. “We need to per­form fewer angi­og­raphies, and that means less con­trast media use and X-ray dose.”

“If there are sev­eral lesions to treat, you don’t have to acquire a new angi­og­raphic image each time. Thanks to the pan­o­rama, we can tar­get the indi­vid­ual lesions that have been marked and measured.”

The lesions can be local­ized and marked on the pan­o­rama. This time the steno­sis is in the popli­teal artery. The EndoNaut work­station calibra­tion func­tion makes it pos­sible to measure the length of the lesion to select the best balloon or stent. With great skill and the help of the naviga­tion func­tion and digi­tal zoom of the EndoNaut work­station, the guide­wire is success­fully passed through the occlusion.

The team checks the guide­wire posi­tion with a live fluo­ro­scopic image that is merged with the pan­o­rama. The ves­sel road­map is updated in real time. If the table or the patient moves, the soft­ware relo­cal­izes the live image using the 2D-2D regis­tra­tion. Dr. Keschenau finds this par­tic­u­larly help­ful in her daily work: “If a patient moves a little during seda­tion, we can quickly ana­tom­ically reori­ent and con­tinue the oper­ation with­out much effort, for example, with sub­sequent angiographies."

“Over­coming the stenosis was extremely diffi­cult in this case. The EndoNaut ves­sel over­lay on the live image gave us the cru­cial infor­ma­tion we needed to pass the lesion with the guide­wire correctly.”

The team also makes fre­quent use of the work­station’s digi­tal zoom fea­ture. In this case, the occlu­sion treated with a stent dur­ing a pre­vi­ous pro­ce­dure and the reste­no­sis are clearly vis­i­ble. Using the digi­tal zoom, any area of the live image can be con­tin­u­ously enlarged. After the team has passed the steno­sis, they initi­ate lysis to locally dis­solve the vascular occlu­sion. After 24 hours of lysis, the team inserts a new stent.

Before the first inter­ven­tion, only the fibular artery was patent to mid-calf. After the pro­ce­dure, the fibular artery is visi­ble all the way to the foot, and the dorsalis pedis artery is sup­ported by the fibu­lar artery col­lat­er­als and well displayed in the angi­og­raphy. Blood flow to the leg is restored and the patient is finally able to walk with­out pain, and sleep through the night.

The team is pleased with the inter­ven­tion out­come. “The EndoNaut ves­sel over­lay on the live image pro­vided the cru­cial infor­ma­tion to pass through the steno­sis,” said Prof. Kalder after the procedure.